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Background The NupulseCV intravascular ventricular assist system (iVAS), which consists of a durable pump placed through the subclavian artery, provides extended-duration ambulatory counterpulsation. This study investigated the effect of iVAS on biventricular cardiac function. Methods and Results We reviewed all heart failure patients who received iVAS implantation as a bridge to transplantation or a bridge to candidacy since April 2016 as part of the iVAS first-in-humans and subsequent feasibility study. We compared data of transthoracic echocardiography performed just before implantation (without iVAS support) and again at 30 days or just before explantation (on iVAS support). Eighteen patients (58.8 ± 7.4 years old and 15 male) received iVAS support for 53 ± 43 days. Fourteen patients were bridged to cardiac replacement therapy after 35 ± 19 days and the remaining 4 patients had been supported for 118 ± 41 days. There were no deaths during iVAS support. At 30 days, there was a significant improvement in left ventricular ejection fraction (16.5% ± 11.9% vs 24.4% ± 12.8%; P = .007) and marked reduction in left atrial size (62.7 ± 35.7 mL/m2 vs 33.8 ± 17.2 mL/m2; P Conclusions Improvement in biventricular cardiac function was observed after 30 days of iVAS support. Further studies should examine the use of this technology as a bridge to recovery.

Contrast-induced acute kidney injury (CI-AKI) is a common complication after exposure to contrast media. Renal ischaemia occurs in the initial stage of CI-AKI, however, there are very few effective measures to improve renal perfusion.A total of 114 patients with an estimated glomerular filtration rate (eGFR) of 60-89 ml/min/1.73mThe primary outcome was observed in 26 patients (6 EECP and 20 control; 11% vs. 35%; P = 0.002). CI-AKI occurred in four patients (0 EECP and 4 control; 0% vs. 7%; P = 0.042). The clearance rate of iopromide in the initial 3 h was significantly different between EECP and control group (59.92 ± 8.84 vs 46.80 ± 9.26 ml/min/1.73 mThis study demonstrates that EECP increases the contrast clearance and may have an effect in reducing the risk of CI-AKI. The study has been registered in Chinese Clinical Trial Registry (ChiCTR 2,000,039,190).

Angina persists for many patients despite modern medical therapy and/or revascularization, and this is referred to as refractory angina. All patients with refractory angina must be treated with aggressive risk factor modification plus optimized medical management. β-Blockers and nitrates are usually first-line agents; however most patients require multiple medications for refractory symptom control. Novel agents, such as ranolazine and ivabradine, as well as non-pharmacologic therapies, such as enhanced external counterpulsation and cardiac rehabilitation, may provide relief or reduction of angina. Other standard treatments such as antiplatelet therapy, lipid reduction therapy, blood pressure control, diabetes control, smoking cessation, and wei1ght control should be part of the management of refractory angina as well.

Background The utility of intra-aortic balloon counterpulsation pumps (IABPs) in low cardiac output states is unknown and no studies have explored the impact of IABP therapy on ventricular workload in patients with advanced heart failure (HF). For these reasons, we explored the acute hemodynamic effects of IABP therapy in patients with advanced HF. Methods We prospectively studied 10 consecutive patients with stage D HF referred for IABP placement before left ventricular assist device (LVAD) surgery and compared with 5 control patients with preserved left ventricular (LV) ejection fraction (EF) who did not receive IABP therapy. Hemodynamics were recorded using LV conductance and pulmonary artery catheters. Cardiac index (CI)-responder and CI-nonresponder status was assigned a priori as being “equal to or above” or below the median of the IABP effect on CI, respectively, within 24 hours after IABP activation. Results Compared with controls, patients with advanced HF had lower LVEF, lower LV end-systolic pressure, lower LV stroke work, and higher LV end-diastolic pressures and volumes before IABP activation. IABP activation reduced LV stroke work primarily by reducing end-systolic pressure. IABP therapy increased CI by a median of 20% as well as increased diastolic pressure time index and the myocardial oxygen supply:demand ratio. Compared with CI-nonresponders, CI-responders had higher systemic vascular resistance, lower right heart filling pressures, and a trend toward lower left heart filling pressures with improved indices of right heart function. Compared with CI-nonresponders, the diastolic pressure time index was increased among CI-responders. Conclusions IABP therapy may be effective at reducing LV stroke work, increasing CI, and favorably altering the myocardial oxygen supply:demand ratio in patients with advanced HF, especially among patients with low right heart filling pressures and high systemic vascular resistance.

External counterpulsation (ECP) is a noninvasive method used to augment cerebral perfusion in ischemic stroke. However, the response of beat-to-beat heart rate variability (HRV) in patients with ischemic stroke during ECP remains unknown.Forty-eight patients with unilateral ischemic stroke at the subacute stage and 14 healthy controls were recruited. Beat-to-beat heart rate before, during, and after ECP was monitored. The frequency components of HRV were calculated using power spectral analysis. Very low frequency (VLF;.04 Hz), low frequency (LF; .04-.15 Hz), high frequency (HF; .15-.40 Hz), total power spectral density (TP;.40 Hz), and LF/HF ratio were calculated.In stroke patients, although there were no statistical differences in all of the HRV components, the HRV at VLF showed a trend of increase during ECP compared with baseline in the left-sided stroke patients (P = .083). After ECP, the HRV at LF and TP remained higher than baseline in the right-sided stroke patients (LF, 209.4 versus 117.9, P = .050; TP, 1275.6 versus 390.2, P = .017, respectively). Besides, the HRV at TP also increased after ECP compared with baseline in the left-sided stroke patients (563.0 versus 298.3, P = .029).Irrespective of the side of the ischemia, patients showed an increased beat-to-beat HRV after ECP. Additionally, sympathetic and parasympathetic cardiac modulations were increased after ECP in patients after right-sided subacute stroke.

Heart failure (HF) affects millions of Americans and causes financial burdens because of the need for rehospitalization. For this reason, health care systems and patients alike are seeking methods to decrease readmissions. We assessed the potential for reducing readmissions of patients with postacute care HF through an educational program combined with enhanced external counterpulsation (EECP). We examined 99 patients with HF who were referred to EECP centers and received heart failure education and EECP treatment within 90 days of hospital discharge from March 2013 to January 2015. We compared observed and predicted 90-day readmission rates and examined results of 6-minute walk tests, Duke Activity Status Index, New York Heart Association classification, and Canadian Cardiovascular Society classification before and after EECP. Patients were treated with EECP at a median augmentation pressure of 280 mm Hg (quartile 1 = 240, quartile 3 = 280), achieved as early as the first treatment. Augmentation ratios varied from 0.4 to 1.9, with a median of 1.0 (quartile 1 = 0.8, quartile 3 = 1.2). Only 6 patients (6.1%) had unplanned readmissions compared to the predicted 34%, p

Lumped parameter model (LPM) is a common numerical model for hemodynamic simulation of human's blood circulatory system. The numerical simulation of enhanced external counterpulsation (EECP) is a typical biomechanical simulation process based on the LPM of blood circulatory system. In order to simulate patient-specific hemodynamic effects of EECP and develop best treatment strategy for each individual, this study developed an optimization algorithm to individualize LPM elements. Physiological data from 30 volunteers including approximate aortic pressure, cardiac output, ankle pressure and carotid artery flow were clinically collected as optimization objectives. A closed-loop LPM was established for the simulation of blood circulatory system. Aiming at clinical data, a sensitivity analysis for each element was conducted to identify the significant ones. We improved the traditional simulated annealing algorithm to iteratively optimize the sensitive elements. To verify the accuracy of the patient-specific model, 30 samples of simulated data were compared with clinical measurements. In addition, an EECP experiment was conducted on a volunteer to verify the applicability of the optimized model for the simulation of EECP. For these 30 samples, the optimization results show a slight difference between clinical data and simulated data. The average relative root mean square error is lower than 5%. For the subject of EECP experiment, the relative error of hemodynamic responses during EECP is lower than 10%. This slight error demonstrated a good state of optimization. The optimized modeling algorithm can effectively individualize the LPM for blood circulatory system, which is significant to the numerical simulation of patient-specific hemodynamics.

Background The key principles regarding what assessments lead to different types of guidance about the use of health technologies (Only in Research, Approval with Research, Approve, or Reject) provide an explicit and transparent framework for technology appraisal. Objective We aim to demonstrate how these principles and assessments can be applied in practice through the use of a seven-point checklist of assessment. Methods The value of access to a technology and the value of additional evidence are explored through the application of the checklist to the case studies of enhanced external counterpulsation for chronic stable angina and clopidogrel for the management of patients with non–ST-segment elevation acute coronary syndromes. Results The case studies demonstrate the importance of considering 1) the expected cost-effectiveness and population net health effects; 2) the need for evidence and whether the type of research required can be conducted once a technology is approved for widespread use; 3) whether there are sources of uncertainty that cannot be resolved by research but only over time; and 4) whether there are significant (opportunity) costs that once committed by approval cannot be recovered. Conclusions The checklist demonstrates that cost-effectiveness is a necessary but not sufficient condition for approval. Only in Research may be appropriate when a technology is expected to be cost-effective due to significant irrecoverable costs. It is only approval that can be ruled out if a technology is not expected to be cost-effective. Lack of cost-effectiveness is not a necessary or sufficient condition for rejection.

Recent studies have focused on the use of fixed-rate intraaortic balloon pumping (IABP) during cardiopulmonary bypass (CPB) to achieve pulsatile flow. Because application of an IABP catheter may represent a functional obstruction within the descending aorta, we explored the effect of IABP-pulsed CPB-perfusion with special attention to perfusion above and below the IABP balloon.Sixteen animals received an IABP catheter that remained turned off position (NP group, n = 8) or was switched to an automatic mode of 80 beats/min during CPB (PP group, n = 8). Flow-data and pressure-data were obtained above and below the IABP balloon. Tissue perfusion was evaluated by microspheres.IABP-pulsed CPB-perfusion, as assessed at 30 minutes on CPB, increased proximal mean aortic pressure (p0.05) and carotid artery blood flow (p0.001), but decreased distal mean aortic pressure (p0.001). The decrease of distal mean aortic pressure in the PP group was associated with a 75 % decrease (p0.001) of renal tissue perfusion. During nonpulsed perfusion the respective variables remained essentially unchanged compared with pre-CPB levels.Using IABP as a surrogate to achieve pulsatile perfusion during CPB contributes significantly to lowered aortic pressure in the distal portion of aorta and impaired tissue perfusion of the kidneys. The results are focusing on effects that may contribute to organ dysfunction and acute kidney injury. Consequently, assessment of perfusion pressure distal to the balloon should be addressed whenever IABP is used during CPB.

A unifying definition of what constitutes high-risk percutaneous coronary intervention remains elusive. This reflects the existence of several recognized patient, anatomic, and procedural characteristics that, when combined, can contribute to elevating risk. The relative inability to withstand the adverse hemodynamic sequelae of dysrhythmia, transient episodes of ischemia-reperfusion injury, or distal embolization of atherogenic material associated with coronary intervention serve as a common thread to tie this patient cohort together. This enhanced susceptibility to catastrophic hemodynamic collapse has triggered the development of percutaneous cardiac assist devices such as the intra-aortic balloon pump, Impella (Abiomed Inc., Danvers, Massachusetts), TandemHeart (CardiacAssist, Inc., Pittsburgh, Pennsylvania), and extracorporeal membranous oxygenation to provide adjunctive mechanical circulatory support. In this state-of-the-art review, we discuss the physiology underpinning their application. Thereafter, we examine the results of several randomized multicenter trials investigating their use in high-risk coronary intervention to determine which patients would benefit most from their implantation and whether there is a signal to delineate whether they should be used in an elective pre-procedure, standby, rescue, or routine post-procedure fashion.

Upper limb weakness and incoordination is a common disability following ischemic stroke. Previous studies have showed that the single application of external counterpulsation (ECP) and intermittent theta burst stimulation (iTBS) can effectively enhance the cortical motor excitability and facilitate recovery. However, it remains uncertain if sequential application of these therapies would further augment the recovery. We hypothesize a synergistic effect of ECP followed by iTBS to upper limb function may happen through improvements in both cerebral perfusion and neuron excitability.

The intra-aortic balloon pump (IABP), which is the main representative of the counterpulsation technique, has been an invaluable tool in cardiologists' and cardiac surgeons' armamentarium for approximately half a century. The IABP confers a wide variety of vaguely understood effects on cardiac physiology and mechano-energetics. Although, the recommendations for its use are multiple, most are not substantially evidence-based. Indicatively, the results of recently performed prospective studies have put IABP's utility in the setting of post-infarction cardiogenic shock into question. However, the particular issue remains open to further research. IABP support in high-risk patients undergoing PCI is associated with favorable long-term clinical outcome. In cardiac surgery, the use of IABP in cases of peri-operative low-output syndrome, refractory angina or ischemia-related mechanical complications is a usual, but poorly justified strategy. Anecdotal cases of treatment of incessant ventricular arrhythmias, reversal of right ventricular dysfunction and partial myocardial recovery have also been reported with its use. Converging data demonstrate the potential of safe long-term IABP support as a bridge to decision making or a bridge to transplantation modality in patients with heart failure. The feasibility of IABP insertion via other than the femoral artery sites enhances this potential. Despite the fact that several other counterpulsation devices have been developed and tested overtime none has managed to substitute the IABP, which continues to be most frequently used mechanical assist device.

Background To investigate the therapeutic value of enhanced external counterpulsation (EECP) on recovery of cerebral blood flow following cardiac arrest (CA) and successful resumption of spontaneous circulation (ROSC) by cardiopulmonary resuscitation. Methods CA models were conducted using beagle dogs induced by alternating current. After successful ROSC by cardiopulmonary resuscitation, 16 dogs were randomly divided into the EECP and control group (n = 8 per group). Dogs underwent dynamic contrast-enhanced and diffusion-weighted magnetic resonance imaging at baseline prior to CA and during the 3 days following ROSC. Mean blood pressure, right common carotid artery blood flow, intracranial microcirculation and blood lactate levels were measured. Neurological outcome was assessed by the neurologic deficit score. Hematoxylin-eosin staining and transmission electron microscopy were performed for morphology and microconstruction of the cerebral cortex. Results The EECP group exhibited a significant elevation in right common carotid artery blood flow, intracranial microcirculation and a substantial decrease in blood lactate levels relative to the control group. Relative cerebral blood flow and volume were higher in the EECP group during the 3 days. Apparent diffusion coefficients were significantly higher in the EECP group on the first and third days. After ROSC, the neurologic deficit score was significantly higher in the control group compared to those in the EECP group during the three days of experiment. The cell swelling of neurons and increase of mitochondrial mass were more pronounced in the control group. Conclusion EECP is beneficial for recovery of cerebral blood flow and attenuation of ischemic cerebral edema following CA and successful ROSC.

Improved pharmacological, invasive, and surgical therapies for cardiovascular diseases over the last few decades have led to an increase in life expectancy of individuals with angina. Despite treatment with multiple medications and invasive procedures, these patients remain symptomatic and functionally limited. Enhanced external counterpulsation (EECP) is a safe, noninvasive, well-tolerated, and clinically effective outpatient physical therapy for many patients with refractory angina. Numerous trials demonstrate positive clinical responses to EECP, including reductions in angina and nitrate use, increase in exercise tolerance, and enhanced quality of life. Several mechanisms are thought responsible for the clinical benefits of this therapy. Despite the marked success rates EECP achieves, the treatment remains largely unknown. This review will summarize the current evidence for the use of EECP and spark a better understanding of the potential role of this treatment.

Cardiogenic shock (CS) is a syndrome of progressive depression of myocardial function with systemic hypoperfusion. It occurs due to various aetiologies such as acute myocardial infarction, myocarditis, acute decompensated heart failure and postcardiotomy. Cardiogenic shock carries poor prognosis, and medical therapy alone is not effective. Mechanical circulatory support is required to unload the ventricles, decrease the myocardial demand, prevent further injury, improve the coronary perfusion, stabilise the haemodynamics and maintain the end-organ perfusion before definitive interventions such as coronary reperfusion can take place. Currently, there are several methods of mechanical circulatory support. These include extracorporeal life support, paracorporeal or extracorporeal ventricular-assist devices, percutaneous ventricular assist devices, intra-aortic balloon counterpulsation and total artificial heart. In this review, we discuss the role of each of these circulatory support devices in the management of acute cardiac failure.

The recent, widespread success of mechanical circulatory support has prompted the development of numerous implantable devices to treat advanced heart failure. It is important to raise awareness of novel device systems, the mechanisms by which they function, and implications for patient management. This article discusses devices that are being developed or are in clinical trials. Devices are categorized as standard full support, less-invasive full support, partial support: rotary pumps, partial support: counterpulsation devices, right ventricular assist device, and total artificial heart. Implantation strategy, mechanism of action, durability, efficacy, hemocompatibility, and human factors are considered. The feasibility of novel strategies for unloading the failing heart is examined.

Enhanced external counterpulsation (EECP) is a noninvasive technique for treatment of symptomatic coronary artery disease in patients not amenable to revascularization procedures. However, the mechanisms underlying the benefits of EECP remain unknown. We hypothesized that decreases in arterial stiffness and aortic wave reflection are a therapeutic target for EECP. Patients with coronary artery disease and chronic angina pectoris were randomized (2:1 ratio) to 35 1-hour sessions of EECP (n = 28) or sham EECP (n = 14). Central and peripheral arterial pulse-wave velocity and aortic wave reflection (augmentation index) were measured using applanation tonometry before, and after 17 and 35 1-hour treatment sessions. Wasted left ventricular pressure energy and aortic systolic tension-time index, markers of left-ventricular myocardial oxygen demand, were derived from the synthesized aortic pressure wave. Exercise duration, anginal threshold, and peak oxygen consumption were measured using a graded treadmill test. Central arterial stiffness and augmentation index were decreased after 17 and 35 sessions in the treatment group. Measurements of peripheral arterial stiffness were decreased after 35 sessions in the treatment group. Changes in aortic pressure wave reflection resulted in decreased measurements of myocardial oxygen demand and wasted left ventricular energy. No changes in central or peripheral arterial stiffness were observed in the sham group. Furthermore, measurements of exercise capacity were improved in the EECP group but unchanged in the sham group. In conclusion, EECP therapy decreases central and peripheral arterial stiffness, which may explain improvements in myocardial oxygen demand in patients with chronic angina pectoris after treatment.

Background Stimulation of collateral artery growth is a promising therapeutic option for patients with coronary artery disease. External counterpulsation is a non-invasive technique suggested to promote the growth of myocardial collateral arteries via increase of shear stress. The Art.Net.2 Trial tests invasively and functionally for the first time the hypothesis whether a treatment course with external counterpulsation (over 7 weeks) can induce the growth of myocardial collateral arteries. Methods This study is designed as a prospective, controlled, proof-of-concept study. Inclusion criteria are (1) age 40 to 80 years, (2) stable coronary disease, (3) a residual significant stenosis of at least one epicardial artery and (4) a positive ischemic stress-test for the region of interest. As primary endpoint serves the pressure-derived collateral flow index (CFIp), the invasive gold-standard to assess myocardial collateral pathways. CFIp is determined by simultaneous measurement of mean aortic pressure ( P a , mm Hg), distal coronary occlusive (wedge) pressure ( P w , mm Hg) and central venous pressure ( P v , mm Hg). The index is calculated as CFIp=( P w − P v )/( P a − P v ). The pressure derived fractional flow reserve (FFR) and the index of microcirculatory resistance (IMR) are assessed as secondary invasive endpoints to investigate the effect of ECP on the myocardial vasculature. The non-invasive secondary endpoints include symptoms (CCS and NYHA classification), treadmill-testing and analysis of shear-stress related soluble proteins. Conclusions The Art.Net.-2 Trial will report within the next months whether direct evidence can be brought that ECP promotes coronary collateral growth in patients with stable angina pectoris.

Management of acute ischemic stroke patients is organized around several priorities aimed at ensuring optimal patient outcomes, the first of which is reperfusion therapy, followed by determination of pathogenic mechanism by provision of a comprehensive workup to determine probable cause of the ischemic stroke or transient ischemic attack, for the purpose of providing appropriate prophylaxis for subsequent events. Provision of secondary prevention measures along with therapies that prevent complications associated with neurologic disability, and evaluation for the most appropriate level of rehabilitation services are the final priorities during acute hospitalization. This article provides an overview of reperfusion therapies and emerging hemodynamic treatments for hyperacute ischemic strokes. Gaps in the scientific evidence that are driving current blood flow augmentation research are identified.

Background and Purpose We hypothesized that symptom improvement from enhanced external counterpulsation (EECP) is related to improved heart rate variability (HRV). Methods This prospective, multicenter study enrolled 27 patients with angina who underwent 48-hour ambulatory electrocardiogram monitoring at baseline, immediately after 35 hours of EECP, and at 1 month. Primary end points included change in time-domain (SD of normal-to-normal intervals) and frequency-domain HRV. Results Twenty-four patients completed the full course of EECP therapy and 3 ambulatory electrocardiograms. There were no significant changes in time-domain HRV measures after EECP. Patients younger than 65 years and those with heart failure had improved SD of normal-to-normal interval after EECP ( P = .02). Although frequency-domain HRV measures did not change in the overall cohort, patients with diabetes had improved daytime low-frequency power ( P = .016). Conclusions There was no significant change in the time- or frequency-domain HRV measures after EECP. In diabetic individuals, there was an increase in low-frequency HRV, which has been associated with reduced mortality.

Background The simultaneous occurrence of coronary artery disease and lung cancer is rare. The best surgical treatment strategy remains controversial: performing a combined procedure with or without the use of extracorporeal circulation (ECC). The aim of this study was to compare the surgical procedure, postoperative complications, and survival of combined surgery with the use of ECC to combined surgery without ECC. Methods Forty-three patients underwent a combined procedure between 1994 and 2005. Twenty-eight patients (25 male and 3 female; mean age, 66 years; range, 54 to 76 years) underwent coronary artery (CA) revascularization with ECC after the lung resection was carried out (on-pump). Fifteen patients (14 male and 1 female; mean age, 71 years; range, 50 to 79 years) had first CA revascularization without ECC followed by lung resection (off-pump). Survival was estimated by the Kaplan-Meier method and analyzed using the log-rank test and the Cox proportional hazard regression model. Results Postoperative complications and hospital survival were not significantly different between groups. However, in the on-pump group late survival was significantly better. Late survival was significantly longer in patients without recurrent vessel disease and with stage I lung cancer. Conclusions These results show no significant difference in using an on-pump or off-pump technique to perform a combined cardiac and lung surgery in relation to postoperative complications and hospital survival. However, our data show a significantly longer late survival period in the on-pump group. Because the off-pump patients were older and had more advanced lung malignancy, the off-pump technique should be continued and evaluated.

The treatment of cardiogenic shock complicating the acute coronary syndromes consists of medical therapy, percutaneous revascularization procedures, cardiac surgery, and the implantation of devices. Medical therapy is limited to different positive inotropic and vasoactive drugs, without any firm evidence of survival benefit using these drugs. Several new pharmacologic compounds are at different stages of clinical research, but are not yet routinely approved for the treatment of cardiogenic shock. The only evidence-based therapy with proven survival benefit is timely revascularization. Intra-aortic balloon pump counterpulsation maintains its central role as supportive treatment in cardiogenic shock patients. Anecdotal evidence is available about the use of ventricular assist devices, cardiac resynchronization therapy, and emergent heart transplantation.

Early revascularization (ERV) in patients with ST-elevation myocardial infarction (STEMI) and cardiogenic shock (CS) reduces mortality rates. Patients admitted to hospitals without revascularization capability have high mortality rates and are not often transferred for ERV.Transfer and direct-admit patients with STEMI from the SHOCK Trial and Registry with left ventricular failure (N = 969) were analyzed to determine benefit of ERV in transfer patients.Transfer patients (46%) were younger and less likely to have prior hypertension, myocardial infarction, and heart failure. They received more aggressive treatment, were revascularized later after CS (median 7.3 vs 3.9 hours, P = .0002), and had similar adjusted inhospital mortality compared with direct-admit patients (55% vs 56%). Inhospital mortality was lower in ERV than no/late revascularization (41% vs 53%, P = .017 for transfer patients; 55% vs 71%, P = .0003 for direct-admit patients). Multiple logistic regression showed that inhospital mortality was associated with age (odds ratio [OR] 1.50 per decade increase, 95% CI 1.31-1.73, P.0001), mean arterial pressure (OR 0.98 per 1 mm Hg increase, 95% CI 0.97-0.99, P.0001), fibrinolysis before CS (OR 0.65, 95% CI 0.52-0.96, P = .040), and ERV (OR 0.70, 95% CI 0.52-0.96, P = .028), but not transfer admission (OR 1.23, 95% CI 0.86-1.74, P = .26).Despite longer time to treatment, transfer patients are a selected population with similar adjusted inhospital mortality and ERV benefit as direct-admit patients. Selected patients with STEMI and CS admitted to hospitals without revascularization capability should be transferred to centers with revascularization capability for immediate angiography.

Objectives To determine if arterial properties and wave reflection characteristics are favorably altered after enhanced external counterpulsation (EECP) treatment in patients with refractory angina. Background Early return of reflected waves from the lower body, resulting from increased arterial stiffness, augments central aortic pressure and increases left ventricular (LV) afterload and myocardial oxygen demand. EECP acutely enhances coronary perfusion (supply) and reduces LV afterload (demand). However, the mechanisms responsible for the sustained beneficial effects of EECP treatment are unclear. Methods Radial artery pressure waveforms were recorded by applanation tonometry and central aortic pressure waveforms generated using a mathematical transfer function in 20 patients with stable refractory angina. Data were collected before and after 34 1-h EECP sessions. Augmentation index (AIa) and timing of the reflected pressure wave were calculated from the aortic waveform. Results EECP treatment caused a decline in AIaand an increase in reflected wave travel time. These modifications in wave reflection characteristics caused a decrease in aortic systolic pressure and wasted LV pressure energy. The average number of angina episodes and Canadian Cardiovascular Society (CCS) class, both decreased in concordance with the physiologic changes due to EECP treatment. Conclusions EECP treatment reduces arterial stiffness and improves wave reflection characteristics in patients with refractory angina. These changes decrease LV afterload and myocardial oxygen demand and reduce the number of angina episodes, therefore enabling patients to participate in continuous exercise programs which in turn may provide long-term benefits and sustained improved quality of life.

Enhanced external counterpulsation (EECP) reduces angina and extends time to exercise-induced ischemia in patients with symptomatic coronary disease. One- and two-center studies and a retrospective case series reported that EECP improves myocardial perfusion in stable angina pectoris. We sought to critically evaluate and quantify the effect of EECP on myocardial perfusion.In 6 US university hospitals, EECP was performed for 35 hours in patients with class II to IV angina who had exercise-induced myocardial ischemia. Symptom-limited quantitative gated technetium Tc 99m sestamibi single photon emission computed tomography exercise perfusion imaging was performed at baseline and 1 month post-EECP. Sestamibi was injected at the same heart rate in both stress tests. Single photon emission computed tomography images were read at a blinded core laboratory.Thirty-seven patients were enrolled, 34 of whom completed pre- and post-EECP stress testing. The mean age was 61 +/- 10 years, 81% were male, 78% had prior revascularization, and 68% had 3-vessel disease. The mean angina class decreased from 2.7 +/- 0.7 at baseline to 1.7 +/- 0.7 after EECP (P.001). Exercise duration increased from 9.1 +/- 3.7 minutes at baseline to 10.2 +/- 3.6 minutes post-EECP (P = .03). The average percentage of tracer uptake, magnitude of reversibility, average thickening fraction, and the left ventricular ejection fraction remained unchanged after EECP.We confirm previous report that EECP reduces angina and improves exercise capacity. There were no significant changes in mean defect magnitude, amount of reversibility, thickening fraction, and ejection fraction measured using myocardial quantitative single photon emission computed tomography imaging when compared at identical pre- and post-EECP heart rates.

Background and purpose: Enhanced external counter pulsation (EECP) is used to treat angina. With sustained treatment this increases collateral circulation to the coronary arteries as well as to the body as a whole. We found some patients who underwent EECP for angina or congestive heart failure who also coincidentally had severe Restless Legs Syndrome (RLS). Case reports are presented. Patients and methods: Six patients with RLS (1F, 5M, ages 55–80) underwent EECP treatment. All patients were given the International RLS Study Group rating scale for RLS (the IRLS) before and immediately after 35 days of EECP treatment. Results: The average IRLS rating scale score of the six patients before treatment was 28.8 (range 23–35), which indicates frequent and moderate to very severe RLS. After 35 days of EECP treatment the IRLS score was 6 (P!0.03), which indicates clinically insignificant RLS. Long-term follow-up in three patients indicates sustained improvement in all three at 3–6 months after EECP was completed (IRLS score 28.3–3.33). Further follow-up in four patients showed sustained improvement in two patients 1 year after EECP was completed. Conclusion: EECP improves RLS symptoms significantly and could be considered as an adjunct treatment for patients with RLS. In some cases, the improvement lasts for months after the course of treatment. In this way EECP is unique and unlike pharmacotherapy which requires continuous daily treatment. Furthermore, our results suggest that decreases in vascular flow influence the peripheral or central nervous system leading to the sensory symptoms of RLS. A larger number of patients studied under blinded conditions is needed to draw further conclusions. q 2004 Elsevier B.V. All rights reserved.

Background Enhanced external counterpulsation (EECP) is effective in treating angina in coronary artery disease patients. Whether EECP produces similar immediate and sustained benefits and freedom from adverse events (MACE) at 1 year in patients with severe systolic dysfunction versus diastolic dysfunction is unknown. Methods and results Data of 746 angina patients with a history of heart failure enrolled in the International EECP Registry were divided into 2 groups: left ventricular ejection fraction (LVEF) ≤35% (S) and LVEF >35% (D). Mean LVEF was 51.0 ± 10.2% in diastolic dysfunction (n = 391) versus 26.3 ± 6.9% in systolic dysfunction (n = 355). At baseline, 92.0% of diastolic dysfunction and 90.9% of systolic had Canadian Cardiovascular Society Class III/IV angina with similar number of anginal episodes and nitroglycerin use. After 32 hours of EECP, angina was reduced by ≥1 class in 71.9% of diastolic versus 72.2% of systolic with similar decreases in anginal episodes and nitroglycerin use. At 1-year 78.1% of diastolic and 75.8% of systolic have less angina than pre-EECP. MACE at 1 year was also comparable (24.4 versus 23.8%). Conclusions The benefits of EECP in heart failure patients were similar regardless of diastolic or systolic dysfunction. The improvement was sustained at 1 year with similar MACE.

ObjectivesIntra-aortic balloon counterpulsation (IABC) can improve post-myocardial infarction (MI) outcomes, but the mechanisms of such effect remain unclear. We hypothesized that IABC augmentation reduces the extent of microvascular obstruction after acute infarction.BackgroundMicrovascular obstruction or “no-reflow” (MO) has been shown to negatively influence left ventricular (LV) remodeling after myocardial infarction (MI).MethodsSeventeen dogs underwent 90 min of coronary artery occlusion followed by reperfusion. Animals were then randomized to either IABC (n = 9) or control (n = 8); IABC augmentation was performed for 24 h after MI. Microvascular obstruction and infarct size by first-pass and delayed contrast-enhanced magnetic resonance imaging (MRI) were measured at 1 and 24 h after reperfusion and compared with postmortem infarct size and MO by microspheres.ResultsMicrovascular obstruction by MRI, expressed as percent LV mass, decreased significantly in IABC (4.9 ± 2.2% to 3.6 ± 1.5%) and increased in controls (3.4 ± 0.5% to 4.9 ± 1.1% from 1 to 24 h, respectively; p < 0.001). Similar results were found for MO defined by microspheres. In the control group, MO increased significantly, during 24 h of study (from 8.8 ± 1.7% to 43.2 ± 11.1% of infarcted myocardium; p < 0.05), whereas not important change was observed in the IABC group (from 21.3 ± 7.1% to 25.8 ± 14.7%; p < 0.05 vs. control at 24 h). Infarct size, measured by MRI, increased in both groups (13.2 ± 1.8 to 15.5 ± 2.1 from 1 to 24 h, respectively; p < 0.05).ConclusionsIntra-aortic balloon counterpulsation augmentation performed after reperfusion improves myocardial perfusion at the tissue level, and reduces the extent of no-reflow caused by microvascular obstruction.

Background The enhancement of diastolic coronary blood flow by the combination of thrombolytic therapy (TT) and intra-aortic balloon counterpulsation (IABP) in experimental studies provides a rationale for their combined use in acute myocardial infarction (MI) complicated by cardiogenic shock. We examined the relation between TT (with and without IABP) and 12-month survival in the SHould We Emergently Revascularize Occluded Coronaries for Cardiogenic ShocK (SHOCK) Trial. Methods and results Among 302 patients with myocardial infarction and cardiogenic shock who were randomized in the SHOCK Trial, 16 had absolute contraindications to TT. Among 150 patients randomly assigned to initial medical stabilization (IMS), 63% received TT, as recommended per protocol, compared with 49% of 152 patients randomly assigned to emergency revascularization, in whom TT was not recommended if immediate angiography was available. IABP deployment, which was protocol-recommended, was used in 86% of patients. The rate of severe bleeding was similar in patients receiving TT and in those not receiving TT (31% vs 26%, P = .37). Among patients randomly assigned to IMS, TT was associated with improved 12-month survival (unadjusted mortality hazard ratio, 0.59; P = .01; mortality hazard ratio adjusted for age and prior MI, 0.62; P = .02). TT was not associated with improved 12-month survival among patients randomly assigned to emergency revascularization (unadjusted mortality hazard ratio, 0.93; P = .76; mortality hazard ratio adjusted for age and prior MI, 1.06, P = .81). The test for interaction of TT and randomization group P value was .16, and there was insufficient statistical power to demonstrate a differential effect of TT on 12-month survival by treatment group assignment. Conclusions Among patients randomly assigned to IMS in the SHOCK Trial, TT was associated with improved 12-month survival and did not significantly increase the risk of severe bleeding.

Data from the International Enhanced External Counterpulsation (EECP) Patient Registry were analyzed to determine which patient characteristics influence improvement in angina class with EECP treatment. Patients with severely disabling angina at baseline, men, and those without a history of smoking are more likely to improve their angina class after EECP, whereas those with diabetes mellitus, prior bypass surgery, and heart failure were less likely to benefit.

Skeletal muscle ventricles (SMVs) are pumping chambers formed from latissimus dorsi muscle. The SMV aortic counterpulsator model has been proven to be stable in the long term and provide effective diastolic pressure augmentation in normal dogs. This study seeks to prove that the aortic counterpulsator model can function effectively in chronic heart failure.In 6 dogs, pericardium-lined SMVs were created from latissimus dorsi muscle and electrically conditioned for fatigue resistance. Each SMV was attached to the descending thoracic aorta with a two-limb bifurcated graft and the aorta ligated between the limbs. The SMV was stimulated to contract during cardiac diastole at 1:2 to 1:3 ratio. Rapid ventricular pacing was initiated at 220 to 230 beats/min for 7 weeks to induce chronic heart failure.SMV contraction resulted in augmentation of the diastolic pressure time-index by 12.1% (32.8+/-15.4 versus 36.1+/-14.7 mm Hg-s, p0.05) at baseline, then by 33.6% (12.9+/-4.4 versus 16.8+/-4.3 mm Hg-s, p0.05) after 7 weeks of rapid ventricular pacing. After 7 weeks of rapid ventricular pacing, SMV counterpulsation provided significant afterload reduction with increases in peak left ventricular ejection velocity and stroke volume of 22.7% (142+/-55 versus 168+/-45 mL/s, p0.05) and 6.2% (13.0+/-5.1 versus 13.7+/-5.2 mL, p0.05), respectively. Coronary blood flow was measured in 3 animals at the 7-week measurement; augmentation averaged 47.6% (0.357+/-0.29 versus 0.432+/-0.26 mL/beat, p0.05).The SMV aortic counterpulsator provides improved cardiac assistance relative to the failing heart.

Enhanced external counterpulsation (EECP) is a noninvasive technique that has shown promise in the treatment of ischemic coronary artery disease. Patients undergoing EECP were tested for alterations in psychosocial state associated with treatment. Overall perception of health and quality of life improved with EECP. There was also significant improvement in levels of depression, anxiety, and somatization but no change in levels of anger or hostility. On most measures, change was more significant for subjects who showed objective evidence of resolution of ischemia. Given the known predictive relationship between depression and mortality from cardiac disease, the improvement in depression scores through EECP indicates a finding of potential importance that may warrant further study in future research.

We hypothesized that diastolic counter-pulsation using aortomyoplasty will increase coronary blood flow.In dogs (n = 6, 20 to 25 kg), the left latissimus dorsi muscle was isolated, wrapped around the descending thoracic aorta, and conditioned by chronic electrical stimulation. Heart failure was induced by rapid ventricular pacing. In a terminal study, left ventricular and aortic pressures, and blood flow in the left anterior descending coronary artery and descending aorta were measured. The endocardial-viability ratio was calculated.Aortomyoplasty increased mean diastolic aortic pressure (70 +/- 5 to 75 +/- 5 mm Hg, p0.05) and reduced peak left ventricular pressure (86 +/- 4 to 84 +/- 4 mm Hg, p0.05), leading to a 16% increase in endocardial-viability ratio (1.29 +/- 0.05 to 1.49 +/- 0.05, p0.05). Coronary blood flow was increased by 15% (8.2 +/- 1.5 to 9.4 +/- 1.6 mL/min, p0.05). During muscle contraction, 2.7 +/- 0.5 mL was ejected from the wrapped aortic segment.These data demonstrate that aortomyoplasty provides successful diastolic counterpulsation after muscle conditioning and heart failure.

OBJECTIVES We examined whether enhanced external counterpulsation (EECP) improves myocardial ischemia, exercise tolerance and cardiac function in patients with coronary artery disease (CAD). BACKGROUND Enhanced external counterpulsation reduces angina and improves exercise tolerance in patients with CAD. Some objective improvements of ischemia by EECP have been reported, but they should be confirmed further. Detailed hemodynamic effects of EECP have been less well documented. METHODS Enhanced external counterpulsation was performed for a total of 35 h in patients with stable CAD (n = 12) who showed evidence of exercise-induced myocardial ischemia despite conventional medical or surgical therapies. All patients had significant stenotic lesions in major coronary arteries. RESULTS Enhanced external counterpulsation improved all exercise test parameters (p < 0.05): exercise duration, time to 1-mm ST segment depression, rate-pressure product at peak exercise and rate-pressure product at 1-mm ST segment depression. Moreover, the prevalence of exercise-induced reversible perfusion defects by thallium scintigraphy decreased after treatment (p < 0.01). Enhanced external counterpulsation did not alter systolic function but improved diastolic filling, left ventricular (LV) end-diastolic pressure (p < 0.05) by cardiac catheterization and LV peak filling rate end-diastolic volume/s (p < 0.01) and time to peak filling rate (p < 0.05) by radionuclide scintigraphy. These hemodynamic improvements were associated with decreased plasma brain natriuretic peptides levels after EECP (p < 0.05). CONCLUSIONS Thus, EECP treatment improves exercise tolerance and reduced myocardial ischemia by thallium scintigraphy in association with improved LV diastolic filling in patients with stable CAD.

Nearly 8 million people in the United States suffer from symptoms of coronary artery disease (CAD). Unfortunately, the population of patients with ischemic coronary disease that is not readily amenable to surgical or percutaneous revascularization continues to grow. For patients who are not candidates for standard revascularization procedures and in whom aggressive medical therapy fails to control symptoms, enhanced external counterpulsation (EECP) is a new, noninvasive outpatient method to improve quality of life by decreasing ischemic symptoms and permit increased activity. We report the case of a 56-year-old woman with severe, symptomatic CAD receiving maximal medical therapy who underwent a course of EECP therapy because she was not a good candidate for other forms of revascularization. She demonstrated dramatic improvement in her anginal symptoms and complete resolution of myocardial ischemia on repeat nuclear stress imaging. This case suggests that EECP is a safe and effective method for reducing symptoms of myocardial ischemia in patients for whom standard percutaneous or surgical revascularization is not suitable treatment.

Background Dynamic aortomyoplasty is an alternative technique to heart transplantation. The goal of our study was to evaluate the benefits of aortic counterpulsation obtained by dynamic thoracic aortomyoplasty in patients with heart failure refractory to pharmacologic treatment and contraindications to heart transplant or cardiomyoplasty. Methods In this study we compared preoperative and postoperative data from five out of six carefully selected patients who were treated with dynamic thoracic aortomyoplasty. This surgical technique wraps the right latissimus dorsi muscle flap around the ascending aorta. This muscle flap was electrically stimulated during diastole, following a muscle-conditioning protocol, to obtain diastolic augmentation. At the 6-month follow-up period we evaluated, invasively and noninvasively, the hemodynamic and clinical effects of aortomyoplasty. Results We observed a significant decrease in the number of hospitalizations ( P = 0.01), NYHA functional class ( P = 0.01), cardiothoracic ratio ( P = 0.02), right ventricular diameter ( P = 0.03), left atrial diameter ( P = 0.04), and pulmonary artery systolic pressure ( P = 0.04); and a significant increase in the 6-minute walking test ( P = 0.01), cardiac index ( P = 0.04), noninvasive evaluation of diastolic augmentation ( P = 0.01), left ventricular shortening fraction ( P = 0.01), and radioisotopic left ventricular ejection fraction ( P = 0.02). We also found a nonsignificant decrease in the left ventricular diameter ( P = 0.08) and wedge pressure ( P = 0.19); and a nonsignificant increase in peak oxygen consumption ( P = 0.13). Conclusions Dynamic thoracic aortomyoplasty in heart failure resulted in an important improvement of hemodynamic parameters, heart functional data, and clinical functional class, when comparing preoperative data with the 6-month follow-up data.

Cardiovascular disease is associated with chronic low-level inflammation, as evidenced by elevated circulating proinflammatory cytokines. Experimental evidence suggests that inflammation can be suppressed under conditions of high shear stress. This study was conducted to examine the effects of enhanced external counterpulsation (EECP), a noninvasive therapy that increases endothelial shear stress, on circulating levels of inflammatory biomarkers and adhesion molecules in patients with angina pectoris. Twenty-one patients were randomly assigned to either 35 1-hour treatments at cuff pressures of 300 mm Hg (EECP; n=12) or 75 mm Hg (sham; n=9). Plasma tumor necrosis factor-alpha, monocyte chemoattractant protein-1, and soluble vascular cell adhesion molecule-1 were measured before and after 35 1-hour sessions of treatment or sham. Patients in the EECP group demonstrated reductions in tumor necrosis factor-alpha (6.9+/-2.7 vs 4.9+/-2.5 pg/ml, p

As the incidence of angina and heart failure continue to rise, new therapeutic options will be needed to treat patients who remain symptomatic or who are intolerant to current treatment. Enhanced external counterpulsation (EECP) is a noninvasive modality being investigated in both angina and congestive heart failure patients. It has been proven to provide symptomatic benefit in angina patients, but has not been proven to show an increase in life expectancy or decrease in cardiovascular events. EECP in heart failure has been proven to be safe, but its efficacy is still uncertain. The present paper summarizes the current literature on the clinical use of EECP in angina and heart failure.

The purpose of this study was to evaluate the effect of sequential external counterpulsation (SECP) on cerebral and renal blood flow. The effect of SECP on carotid and renal artery blood flow was studied in 35 and 18 patients, respectively. With a portable unit, cuffs were applied to the calves and thighs, sequentially inflated with air at the onset of diastole, and deflated at the onset of systole. Carotid and renal artery Duplex studies were performed during intermittent SECP. Flow velocity and flow velocity integral were measured at baseline and during SECP. Diastolic augmentation of carotid and renal artery flow velocity was observed in all patients. The mean carotid flow velocity integral increased by 22% from 27.7 ± 1.8 cm to 33.1 ± 2.3 cm ( P = 0.001). The mean renal artery flow velocity integral increased by 19% from 21 ± 1 cm to 25 ± 1 cm ( P = 0.0001). With SECP, a new diastolic Doppler flow velocity wave was observed, with an average peak carotid diastolic flow velocity of 56 ± 4 cm/sec and an average peak renal artery diastolic flow velocity of 40 ± 2.5 cm/sec. This diastolic wave was 75% (carotid) and 68% (renal) as high as the systolic wave during SECP. In addition, with SECP the systolic wave increased by 6% and 8% in the carotid and renal artery, respectively ( P = 0.02 and 0.006, respectively). In conclusion, SECP significantly increases carotid and renal blood flow. This noninvasive, harmless treatment may be useful to support patients with decreased cerebral and renal perfusion.

With increasing experience, off-pump coronary artery bypass grafting for high-risk patients can be performed safely. However, in patients who need intraaortic balloon counterpulsation support, mistriggering of intraaortic balloon counterpulsation during mobilization of the heart can induce unstable hemodynamic conditions. My colleagues and I have developed a simple method of detecting the trigger signal accurately: an epicardial pacemaker wire is placed close to the apex of the left ventricle, and 1 precordial V lead is disconnected and then linked to the epicardial pacemaker wire. This method provides an excellent detection of R-wave potentials in any position of the heart throughout an entire off-pump coronary artery bypass grafting procedure.

The paraaortic counterpulsation device is a round pumping chamber with one valveless opening 20 mm in diameter and a 100 ml stroke volume. The paraaortic counterpulsation device was implanted on the ascending aorta of three male patients with intractable cardiogenic shock. Patients were assisted for 4 hours and 8 and 54 days, respectively; the first patient died as a result of nonresponding peripheral vasodilation and the other two died of septic shock. The two patients who were assisted for 8 and 54 days were conscious and able to function in a limited manner during the mechanical assistance. Discontinuation of the mechanical support for a few seconds was followed by low systolic arterial pressure (30 to 60 mm Hg) and syncopal episodes. Biochemical tests and autopsy results in these patients showed no evidence of blood cell destruction, thrombus formation, brain infarction, or other distal emboli. In conclusion, satisfactory hemodynamic effects, excellent biocompatibility, and simplicity of the implantation procedure in these patients encourage the use of the paraaortic counterpulsation device as a bridge to heart transplantation. (J THORAC CARDIOVASC SURG 1996;111:55-61)

Skeletal muscle ventricles (SMVs) were constructed from the latissimus dorsi muscle in 15 beagles. The animals were divided into two groups based on modifications in the SMV construction: group I consisted of 5 animals and group II of 10 animals. After a 3-week vascular delay and 6 to 8 weeks of 2-Hz electrical conditioning, the SMVs were connected to the thoracic aorta, In group I, counterpulsation at 33 Hz resulted in an initial 24.4% augmentation of the mean diastolic pressure, a 27.1% decrease in the presystolic pressure, and a 15.9% increase in the endocardial viability ratio. In group II, the mean diastolic pressure rose by 24.7%, the presystolic pressure decreased by 14.3%, and the endocardial viability ratio increased by 24.5%. During propranolol-induced heart failure, the percentage increase in the mean diastolic pressure was improved (12.9% before propranolol infusion versus 27.6% during propranolol infusion), as was the percentage increase in the endocardial viability ratio (11.2% versus 28.7%). Under low cardiac output conditions, SMV contraction resulted in small but statistically significant increases in the total cardiac output (4.3% at 33 Hz, 7.6% at 85 Hz). One animal in group I survived for 589 days with a functioning SMV before progressive dilation of the SMV (impending rupture) developed. Delayed rupture of the SMV sewing ring anastomosis occurred in 2 dogs. Five animals in group II are all alive, with functioning SMVs in the circulation for 377 to 464 days. No animals in group II had rupture of their SMV or showed evidence of thrombus formation.

Aortomyoplasty consists of wrapping the latissimus dorsi muscle (LDM) around the ascending aorta and electrostimulating it during diastole. The ascending aorta will act as an ectopic neo-ventricle compressed during diastole, thus reproducing the effects of longterm diastolic counterpulsation. In 5 goats, the right LDM was transferred to the thoracic cavity after removal of the second rib. The ascending aorta was enlarged by a pericardial patch and wrapped with the LDM. Postoperative electrostimulation was delivered in a counterpul-sating manner. Hemodynamic studies were performed at 12 and 24 months postoperatively. Percent increase in the subendocardial viability index (diastolic pressure-time index/systolic tension-time index) was calculated using unassisted and assisted cardiac cycles with the stimulator off versus the stimulator on at a 1:1 ratio in the basal state and after acute heart failure was induced by the administration of high doses of propranolol hydrochloride. Diastolic counterpulsation of the ascending aorta resulted in significant improvement in the subendocardial viability index long term, both in basal state conditions and after induced cardiac failure. During heart failure, aortomyoplasty increased the cardiac output and decreased systemic vascular resistance. Histopathologic studies up to 24 months showed preservation of the histologie structure of the aortic wall and no evidence of thromboembolism. Tight adhesions developed between the aortic wall (including the pericardial patch) and the LDM. The diameters of the enlarged aortas showed no significant differences compared with diameters immediately postoperatively. In conclusion, aortomyoplasty produces chronic diastolic augmentation with preservation of aortic structure. After induction of heart failure, aortomyoplasty offers efficient circulatory support.

temic venous return, and reduces ventricular afterload. 1‐3 We hypothesized that EC could benefit patients who underwent the Fontan procedure by improving cardiac output in the early postoperative period. EC had not been studied in the postoperative setting, and had never previously performed in the pediatric population. Therefore, this investigation sought to provide preliminary evidence of EC safety and short-term efficacy in children after Fontan surgery. ••• We performed a prospective, within-patient, controlled investigation of EC in children who underwent the Fontan procedure (fenestrated and nonfenestrated) at Children’ s Medical Center, Dallas, from May 1999 to June 2001. Children were considered for participation in the study if they were consecutive pediatric patients for whom parental consent was obtained, if there was an EC machine available, and if EC cuff sizes were deemed appropriate (pediatric-sized cuff straps able to be tightened over a sheepskin barrier to prevent excessive movement and skin irritation during EC). Patients were excluded from study for the following reasons: significant intraoperative surgical complications that may have compromised postoperative neurologic status (defined as 10 minutes of hypotension off bypass with blood pressure less than the fifth percentile for age), extubation before or immediately upon arrival to the cardiac intensive care unit, presence of a cardiac arrhythmia or paced heart rhythm, invasive line(s) in the femoral or lower extremities, peripheral vascular disease, musculoskeletal anomaly involving the lower extremities, significant and prolonged postoperative hemorrhage (3 ml/kg/ hour persisting for 10 hours after arrival to the cardiac intensive care unit), or aortic insuf ficiency. After admission to the cardiac intensive care unit, each patient was assessed for clinical stability. Blood products and/or volume (5% albumin) were administered and inotropes were adjusted at the discretion of the attending physician based on hemodynamic status, chest tube drainage, hemoglobin level, and degree of anticoagulation. Intravenous fluid was administered before the investigation if systemic perfusion was determined to be clinically poor, or if systolic blood pressure decreased below the fifth percentile for age at any time. The study protocol was initiated while patients were sedated and anesthetized with midazolam and fentanyl, before extubation, and after mediastinal blood loss was controlled (3 ml/kg/hour). Inotropes and vasoactive medications were unchanged during the period of investigation. The study protocol was divided into 3 10-minute periods. During the first period, baseline parameters were measured before initiation of EC. This was immediately followed by a 10-minute EC period, and directly thereafter, a postintervention period. The hemodynamic parameters obtained during all 3 periods included cardiac index (CI) by ascending aortic pulse Doppler echocardiography (averaged over 8 cardiac cycles), 4 vital signs (heart rate, blood pressure), and central venous pressure (CVP). Each parameter was measured every minute during the 3 study intervals, except ascending aortic Doppler flow, which was evaluated every 2 minutes. Echocardiographic determinations of CI were made off-line by a single interpreter who was blinded to the period of testing. Blinded interpretation was feasible because EC does not alter ascending aortic Doppler flow patterns.5 Chest tube output and oxygen saturation were recorded throughout the investigation. EC was performed using the Cardiomedics Cardi

Pulmonary artery balloon counterpulsation is a promising experimental technique for treatment of right ventricular failure. However, clinical application has been limited in that the only device presently available (the large-volume intraaortic balloon) must be placed within a synthetic graft. Because a balloon with a smaller volume (which could be placed through a peripheral vein and be contained entirely within the pulmonary artery) would make the technique feasible on a wider scale, we tested an 8-mL pulmonary artery balloon placed through the femoral vein in 12 dogs. Two groups of animals were compared. One group had the pulmonary artery balloon in place but not counterpulsating; the other had the pulmonary artery balloon in place and counterpulsating. Each group was studied for 12 hours. A variety of hemodynamic parameters were measured. Effective diastolic augmentation and systolic unloading were noted in all 6 dogs that underwent counterpulsation (5.0 ± 1.1 mm Hg of diastolic augmentation and 9.5 ± 1.6 mm Hg of systolic unloading). Pulmonary function, as measured by arterial blood gas sampling and pulmonary vascular resistance, was not impaired. Examination of the heart and lungs showed no detrimental pathologic effects of pulmonary artery balloon counterpulsation. Placement of the balloon through a peripheral vein with a guidewire was easy and uncomplicated. We conclude that pulmonary artery balloon counterpulsation is safe over an extended period of 12 hours in the canine model and that diastolic augmentation and systolic unloading can be produced.