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BackgroundHistological examination of the effects of balloon angioplasty have been described from in vitro experiments and a limited number of pathologic specimens. Intravascular ultrasound imaging permits real time cross-sectional observation of the effect of balloon dilation on the atherosclerotic plaque in vivo.Methods and resultsThe morphological effects of coronary angioplasty were visualized at 66 lesions in 47 patients immediately after balloon dilatation with an intravascular ultrasound imaging catheter. Cross-sectional images were obtained at 30 frames per second as the catheter passed along the length of the artery. Quantitative and qualitative assessments of the dilated atherosclerotic plaque were made from the angiograms and the ultrasound images. Six morphological patterns after angioplasty were appreciated by ultrasound imaging. Type A consists of a linear, partial tear of the plaque from the lumen toward the media (seven lesions); Type B is defined by a split in the plaque that extends to the media (12 lesions); Type C demonstrates a dissection behind the plaque that subtends an arc of up to 180 degrees around the circumference (18 lesions); Type D was a more extensive dissection that encompasses an arc of more than 180 degrees (four lesions); and Type E may be present in either concentric (Type E1, 14 lesions) or eccentric (Type E2, 11 lesions) plaque and is defined as an ultrasound study without any evidence of a fracture or a dissection in the plaque. There was a large amount of residual atheroma in each type of morphology (7.8 +/- 2.9 mm2, 61.6 +/- 15.4% of cross-sectional area); there was no difference, however, in lumen or atheroma cross-sectional area among these six patterns. There was a good correlation between ultrasound and angiography for the recognition of a dissection. Calcification was seen in only 14% of lesions on angiography, whereas most lesions (83%) revealed calcification on ultrasound imaging. As determined by intravascular ultrasound, calcified plaque was more likely to fracture in response to balloon dilatation than noncalcified plaque (p less than 0.01). Thirteen of 66 lesions (20%) developed clinical and angiographic restenosis. Restenosis was more likely to occur when the original dilatation left a concentric plaque without a fracture or dissection (Type E1, 50% incidence) compared with a mean restenosis rate of 12% in the remaining morphological patterns (p = 0.053).ConclusionsIntravascular ultrasound provides a more complete quantitative and qualitative description of plaque geometry and composition than angiography after balloon angioplasty. In addition, intravascular ultrasound identified a subset of atherosclerotic plaque that has a higher incidence of restenosis. This information could be used prospectively to consider other therapeutic options in this subset. Intravascular ultrasound provides a method to describe the effects of angioplasty that will be useful in comparing future coronary intervention studies.

Background: In the BEST-CLI trial (Best Endovascular Versus Best Surgical Therapy for Patients With Chronic Limb-Threatening Ischemia), a prespecified secondary objective was to assess the effects of revascularization strategy on health-related quality of life (HRQoL)., Methods: Patients with chronic limb-threatening ischemia were randomized to surgical bypass (Bypass) or endovascular intervention (Endo) in 2 parallel trials. Cohort 1 included patients with single-segment great saphenous vein; cohort 2 included those lacking suitable single-segment great saphenous vein. HRQoL was assessed over the trial duration using Vascular Quality-of-Life (VascuQoL), European Quality-of-Life-5D (EQ-5D), the Short Form-12 (SF-12) Physical Component Summary (SF-12 PCS), SF-12 Mental Component Summary (SF-12 MCS), Utility Index Score (SF-6D R2), and numeric rating scales of pain. HRQoL was summarized by cohort and compared within and between groups using mixed-model linear regression., Results: A total of 1193 and 335 patients in cohorts 1 and 2 with a mean follow-up of 2.9 and 2.0 years, respectively, were analyzed. In cohort 1, HRQoL significantly improved from baseline to follow-up for both groups across all measures. For example, mean (SD) VascuQoL scores were 3.0 (1.3) and 3.0 (1.2) for Bypass and Endo at baseline and 4.7 (1.4) and 4.8 (1.5) over follow-up. There were significant group differences favoring Endo when assessed with VascuQoL (difference, -0.14 [95% CI, -0.25 to -0.02]; P =0.02), SF-12 MCS (difference, -1.03 [95% CI, -1.89 to -0.18]; P =0.02), SF-6D R2 (difference, -0.01 [95% CI, -0.02 to -0.001]; P =0.03), numeric rating scale pain at present (difference, 0.26 [95% CI, 0.03 to 0.49]; P =0.03), usual level during previous week (difference, 0.26 [95% CI, 0.04 to 0.48]; P =0.02), and worst level during previous week (difference, 0.29 [95% CI, 0.02 to 0.56]; P =0.04). There was no difference between treatment arms on the basis of EQ-5D (difference, -0.01 [95% CI, -0.03 to 0.004]; P =0.12) or SF-12 PCS (difference, -0.41 [95% CI, -1.2 to 0.37]; P =0.31). In cohort 2, HRQoL also significantly improved from baseline to the end of follow-up for both groups based on all measures, but there were no differences between Bypass and Endo on any measure., Conclusions: Among patients with chronic limb-threatening ischemia deemed eligible for either Bypass or Endo, revascularization resulted in significant and clinically meaningful improvements in HRQoL. In patients with an available single-segment great saphenous vein for bypass, but not among those without one, Endo was statistically superior on some HRQoL measures; however, these differences were below the threshold of clinically meaningful difference., Competing Interests: Disclosures M.T.M. is an advisor to Janssen. A.F. is an advisor to Sanifit. K.R. receives income as a consultant or member of a scientific advisory board for the following entities: Abbott Vascular, Althea Medical, Angiodynamics, Auxetics, Becton-Dickinson, Boston Scientific, Contego, Crossliner, Innova Vascular, InspireMD, Janssen/Johnson and Johnson, Magneto, Mayo Clinic, MedAlliance, Medtronic, Neptune Medical, Penumbra, Philips, Surmodics, Terumo, Thrombolex, Truvic, Vasorum, and Vumedi. K.R. owns equity or stock options in the following entities: Access Vascular, Aerami, Althea Medical, Auxetics, Contego, Crossliner, Cruzar Systems, Endospan, Imperative Care/Truvic, Innova Vascular, InspireMD, JanaCare, Magneto, MedAlliance, Neptune Medical, Orchestra, Prosomnus, Shockwave, Skydance, Summa Therapeutics, Thrombolex, Vasorum, and Vumedi. K.R. or his institution (on his behalf) receives research grants from the following entities: National Institutes of Health, Abiomed, Boston Scientific, Novo Nordisk Foundation, Penumbra, and Gettinge-Atrium. K.R. serves as a member of the board of directors of the National Pulmonary Embolism Response Team Consortium. M.S.C. is a Data Safety Monitoring Board member for an Abbott Vascular Clinical Trial. J.J.S. received an education grant from WL Gore paid to Boston University and an education grant from Becton Dickinson paid to Boston University. M.D.D. is a consultant for Cook Medical, WL Gore, and Boston Scientific. M.R.J. is a part-time employee for Boston Scientific. B.G. is a consultant to Surmodics and Hart Clinical Consultants. J.A.K. was a consultant and speaker for Cook Medical during the time of the study. The other authors report no conflicts.

The United States has the highest maternal mortality rates among developed countries, and cardiovascular disease is the leading cause. Therefore, the American Heart Association has a unique role in advocating for efforts to improve maternal health and to enhance access to and delivery of care before, during, and after pregnancy. Several initiatives have shaped the time course of major milestones in advancing maternal and reproductive health equity in the United States. There have been significant strides in improving the timeliness of data reporting in maternal mortality surveillance and epidemiological programs in maternal and child health, yet more policy reforms are necessary. To make a sustainable and systemic impact on maternal health, further efforts are necessary at the societal, institutional, stakeholder, and regulatory levels to address the racial and ethnic disparities in maternal health, to effectively reduce inequities in care, and to mitigate maternal morbidity and mortality. In alignment with American Heart Association's mission "to be a relentless force for longer, healthier lives," this policy statement outlines the inequities that influence disparities in maternal outcomes and current policy approaches to improving maternal health and suggests additional potentially impactful actions to improve maternal outcomes and ultimately save mothers' lives.

In 2021, the American Heart Association celebrates its 40th anniversary in advocacy. This policy statement details the arc of the organization's nonpartisan, evidence-based, equity-focused approach to advocating for public policy change, highlighting key milestones and describing the core components of the association's capacity and activity at all levels of government. This policy statement presents a vision and strategic imperative for future American Heart Association advocacy efforts to inform and influence policy changes that advance equitable, impactful societal solutions that transform and improve cardiovascular health for everyone. The American Heart Association maintains accountability by measuring and evaluating the totality of this work and its impact on equitable health outcomes. The American Heart Association will apply these lessons to constantly refine its own strategic policy focus and advocacy efforts. The association will also serve as a resource and catalyst to other organizations working to engage and educate policy makers, partners, the media, and funders about the important role and contribution of public policy change to achieve shared goals.

Background: Paclitaxel-containing devices (PTXDs) significantly reduce reintervention in patients with symptomatic femoropopliteal peripheral artery disease. A recent aggregate-data meta-analysis reported increased late mortality in patients with peripheral artery disease treated with PTXDs. We performed an individual patient data meta-analysis to evaluate mortality., Methods: Manufacturers of US Food and Drug Administration-approved and commercially available devices in the United States provided deidentified individual patient data for independent analysis. Cox proportional hazards 1-stage meta-analysis models using intention-to-treat methods were used for the primary analysis. A secondary analysis of recovered missing vital status data was performed. The impact of control crossover to PTXDs, cause-specific mortality, and drug dose mortality were assessed., Results: A total of 2185 subjects and 386 deaths from 8 PTXD trials with 4-year median follow-up were identified. The primary analysis indicated a 38% (95% CI, 6% to 80%) increased relative mortality risk, corresponding to 4.6% absolute increase, at 5 years associated with PTXD use. Control and treatment arm loss to follow-up and withdrawal were 24% and 23%, respectively. With inclusion of recovered vital status data, the excess relative mortality risk was 27% (95% CI, 3%-58%). This observation was consistent across various scenarios, including as-treated analyses, with no evidence of increased risk over time with PTXDs. Mortality risk tended to be increased for all major causes of death. There were no subgroup differences. No drug dose-mortality association was identified., Conclusions: This individual patient data meta-analysis, based on the most complete available data set of mortality events from PTXD randomized controlled trials, identified an absolute 4.6% increased mortality risk associated with PTXD use.

Paclitaxel drug-coated balloons and drug-eluting stents became commercially available for the treatment of intermittent claudication in 2015 and 2012, respectively. Both devices demonstrated superiority in limb revascularization compared with non-paclitaxel-coated devices and were rapidly accepted into clinical practice. In a recent systematic review and study-level meta-analysis, Katsanos et al reported a late all-cause mortality signal for patients in the drug-coated balloon and drug-eluting stent arms of randomized clinical trials for both devices. As a result of this safety signal, Vascular InterVentional Advances Physicians (VIVA), a not-for-profit 501c(3) organization, convened the Vascular Leaders Forum on March 1 and 2, 2019, in Washington, DC, to initiate an open and collaborative process of investigation into this finding. The Vascular Leaders Forum brought together 100 stakeholders, including an international group of representatives of cardiovascular medicine, interventional radiology, vascular medicine, and vascular surgery; oncologists; basic scientists; the Food and Drug Administration; the Centers for Medicare and Medicaid Services; and commercial manufacturers of these products. The Vascular Leaders Forum reviewed the natural history of peripheral arterial disease, the use of paclitaxel in peripheral arterial disease and other conditions, the harm signal noted by Katsanos et al, the impact of the methods chosen by Katsanos et al, possible mechanisms of harm, the role of the Food and Drug Administration in a setting like this one, and guidance for clinicians taking care of patients with symptomatic peripheral arterial disease. This document integrates the most current data to help establish an appropriate path forward to understand the risks and benefits associated with these technologies while ensuring the best treatment paradigm for patients.

This publication describes uniform definitions for cardiovascular and stroke outcomes developed by the Standardized Data Collection for Cardiovascular Trials Initiative and the US Food and Drug Administration (FDA). The FDA established the Standardized Data Collection for Cardiovascular Trials Initiative in 2009 to simplify the design and conduct of clinical trials intended to support marketing applications. The writing committee recognizes that these definitions may be used in other types of clinical trials and clinical care processes where appropriate. Use of these definitions at the FDA has enhanced the ability to aggregate data within and across medical product development programs, conduct meta-analyses to evaluate cardiovascular safety, integrate data from multiple trials, and compare effectiveness of drugs and devices. Further study is needed to determine whether prospective data collection using these common definitions improves the design, conduct, and interpretability of the results of clinical trials., (© 2018 American Heart Association, Inc.)

Background: In patients with symptomatic peripheral artery disease with a history of limb revascularization, the optimal antithrombotic regimen for long-term management is unknown., Methods: The EUCLID trial (Examining Use of Ticagrelor In PAD) randomized 13 885 patients with peripheral artery disease to treatment with ticagrelor 90 mg twice daily or clopidogrel 75 mg daily. Patients were enrolled based on an abnormal ankle-brachial index ≤0.80 or a previous lower extremity revascularization. This analysis focuses on the 7875 (57%) patients enrolled based on the previous lower extremity revascularization criterion. Patients could not be enrolled within 30 days of most recent revascularization, and patients with an indication for dual antiplatelet therapy were excluded. The primary efficacy end point was a composite of cardiovascular death, myocardial infarction, or ischemic stroke. The primary safety end point was major bleeding., Results: Patients with a previous revascularization had a mean age of 66 years, 73% were male, and the median baseline ankle-brachial index was 0.78. After adjustment for baseline characteristics, patients enrolled based on previous revascularization had similar rates of the primary composite end point (hazard ratio [HR] 1.10, 95% confidence interval [CI] 0.98-1.23, P=0.12) and statistically significantly higher rates of myocardial infarction (HR 1.29, 95% CI 1.08-1.55, P=0.005) and acute limb ischemia (HR 4.23, 95% CI 2.86-6.25, P<0.001) when compared with patients enrolled based on ankle-brachial index criteria. No differences in ticagrelor- versus clopidogrel-treated patients were found for the primary efficacy end point (11.4% vs 11.3%; HR 1.01, 95% CI 0.88-1.15; P=0.90), all-cause mortality (9.2% vs 9.2%; HR 0.99, 95% CI 0.86-1.15; P=0.93), acute limb ischemia (2.5% vs 2.5%; HR 1.03, 95% CI 0.78-1.36; P=0.84), or major bleeding (1.9% vs 1.8%; HR 1.15, 95% CI 0.83-1.59; P=0.41). The median duration of follow-up was ≈30 months., Conclusions: After adjustment for baseline characteristics, patients enrolled based on previous revascularization for peripheral artery disease had higher rates of myocardial infarction and acute limb ischemia, with similar composite rates of cardiovascular death, myocardial infarction, and stroke when compared with patients enrolled based on the ankle-brachial index criterion. No significant differences were found between ticagrelor and clopidogrel for reduction of cardiovascular or acute limb events., Clinical Trial Registration: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01732822., (© 2016 American Heart Association, Inc.)

Background: Tremendous advances have occurred in therapies for peripheral vascular disease (PVD); until recently, however, it has not been possible to examine the entire clinical trial portfolio of studies for the treatment of PVD (both arterial and venous disease)., Methods and Results: We examined interventional trials registered in ClinicalTrials.gov from October 2007 through September 2010 (n=40,970) and identified 676 (1.7%) PVD trials (n=493 arterial only, n=170 venous only, n=13 both arterial and venous). Most arterial studies investigated lower-extremity peripheral artery disease and acute stroke (35% and 24%, respectively), whereas most venous studies examined deep vein thrombosis/pulmonary embolus prevention (42%) or venous ulceration (25%). A placebo-controlled trial design was used in 27% of the PVD trials, and 4% of the PVD trials excluded patients >65 years of age. Enrollment in at least 1 US site decreased from 51% of trials in 2007 to 41% in 2010. Compared with noncardiology disciplines, PVD trials were more likely to be double-blinded, to investigate the use of devices and procedures, and to have industry sponsorship and assumed funding source, and they were less likely to investigate drug and behavioral therapies. Geographic access to PVD clinical trials within the United States is limited to primarily large metropolitan areas., Conclusions: PVD studies represent a small group of trials registered in ClinicalTrials.gov, despite the high prevalence of vascular disease in the general population. This low number, compounded by the decreasing number of PVD trials in the United States, is concerning and may limit the ability to inform current clinical practice of patients with PVD., (© 2014 American Heart Association, Inc.)

Background: To evaluate outcomes after carotid artery stenting in larger real-world populations, the Food and Drug Administration mandated that companies conduct postmarketing surveillance (PMS) studies of approved stent systems. Whether PMS studies are representative of carotid artery stenting in routine clinical practice has not been established., Methods and Results: Within the National Cardiovascular Database Registry-Carotid Artery Revascularization and Endarterectomy (NCDR CARE) Registry, we compared patient and procedural characteristics, in-hospital outcomes, and subsequent all-cause mortality after carotid artery stenting in PMS study participants and nonparticipants. We conducted both crude and propensity score-adjusted comparisons for all outcomes between groups. Compared with nonparticipants, participants in PMS studies had lower rates of symptomatic carotid artery disease within the preceding 6 months, prior stroke, and acute evolving stroke at baseline. The PMS study participants had lower unadjusted rates of combined in-hospital death, stroke, or myocardial infarction (2.3% versus 4.1%; P<0.001), driven by lower rates of stroke (1.7% versus 2.7%; P=0.005) and death (0.3% versus 1.4%; P<0.001). Differences in survival persisted after propensity score adjustment (odds ratio, 0.44; 95% confidence interval, 0.21 to 0.95; P=0.04 for in-hospital mortality; and hazard ratio, 0.80; 95% confidence interval, 0.66 to 0.97; P=0.02 for 2-year mortality). Baseline differences in neurological history explained the largest proportion of the difference in outcomes between groups., Conclusions: Participants in PMS studies for carotid artery stenting have different clinical and procedural characteristics and lower mortality compared with nonparticipants. Extrapolating results from PMS studies of carotid artery stenting to larger real-world settings should be done only with great caution.

Peripheral arterial disease is one manifestation of systemic atherosclerosis. The prevalence of peripheral arterial disease increases with the age of the population. It is important to remember the significant association of coincident coronary artery disease, which is the major cause of mortality in these patients. Remarkable technological advances in the past decade, along with patient preference, have shifted revascularization strategies from traditional open surgical approaches toward lower-morbidity percutaneous endovascular treatments. The availability of stents, more than any other advance, has fueled the growth of catheter-based procedures by improving the safety, durability, and predictability of percutaneous revascularization.

Background: The presence of angiographically identified intracoronary thrombus has been variably associated with complications after coronary angioplasty. Angiography has been shown to be less sensitive than angioscopy for detecting subtle details of intracoronary morphology, such as intracoronary thrombi. The clinical importance of thrombi detectable by angioscopy but not by angiography is not known., Methods and Results: Percutaneous coronary angioscopy was performed in 122 patients undergoing conventional coronary balloon angioplasty (PTCA) at six medical centers. Unstable angina was present in 95 patients (78%) and stable angina in 27 (22%). Therapy was not guided by angioscopic findings, and no patient received thrombolytic therapy as an adjunct to angioplasty. Coronary thrombi were identified in 74 target lesions (61%) by angioscopy versus only 24 (20%) by angiography. A major in-hospital complication (death, myocardial infarction, or emergency bypass surgery) occurred in 10 of 74 patients (14%) with angioscopic intracoronary thrombus, compared with only 1 of 48 patients (2%) without thrombi (P = .03). In-hospital recurrent ischemia (recurrent angina, repeat PTCA, or abrupt occlusion) occurred in 19 of 74 patients (26%) with angioscopic intracoronary thrombi versus only 5 of 48 (10%) without thrombi (P = .03). Relative risk analysis demonstrated that angioscopic thrombus was strongly associated with adverse outcomes (either a major complication or a recurrent ischemic event) after PTCA (relative risk, 3.11; 95% CI, 1.28 to 7.60; P = .01) and that angiographic thrombi were not associated with these complications (relative risk, 0.85; 95% CI, 0.36 to 2.00; P = .91)., Conclusions: The presence of intracoronary thrombus associated with coronary stenoses is significantly underestimated by angiography. Angioscopic intracoronary thrombi, the majority of which were not detected by angiography, are associated with an increased incidence of adverse outcomes after coronary angioplasty.

Background: Patients with diabetes mellitus have a higher prevalence of atherosclerotic heart disease and a higher incidence of myocardial infarction than the general population. Diabetic patients also have several hematologic, rheologic, and metabolic abnormalities not present in their nondiabetic counterparts that may predispose them to atherosclerotic plaque rupture and intraluminal thrombosis and consequently may lead to the formation of morphologically complex plaques and the development of acute coronary syndromes., Methods and Results: Percutaneous coronary angioscopy was performed in 55 consecutive patients with unstable angina. We observed plaque color, texture, and the incidence of intracoronary thrombus associated with the culprit lesions of these patients. The population consisted of 17 (31%) diabetic and 38 (69%) nondiabetic patients. The presence of coronary risk factors was not significantly different between the two populations. Ulcerated plaque was found in 16 of 17 (94%) diabetic patients versus 23 of 38 (60%) nondiabetic patients (P = .01). Intracoronary thrombi were seen in 16 of 17 (94%) diabetic patients versus 21 of 38 (55%) nondiabetic patients (P = .004)., Conclusions: The results of the angioscopic examination show that diabetic patients with unstable angina have a higher incidence of plaque ulceration and intracoronary thrombus formation than nondiabetic patients. This increased frequency of complex lesion morphology is consistent with the disproportionately higher risk for development of acute coronary syndromes in these patients.

Background: Cardiac allograft vasculopathy remains the leading limitation to long-term survival after cardiac transplantation. While the influence of donor and recipient gender in the pathogenesis of cardiac vasculopathy is still poorly understood, studies have indicated that female allografts may be at higher risk for the development of cardiac allograft vasculopathy. The purpose of this study was to characterize the influence of donor and recipient gender on the early genesis of cardiac allograft vasculopathy by using intravascular ultrasound., Methods and Results: Thirty-six consecutive cardiac transplant recipients were divided into three groups on the basis of donor and recipient gender as follows: group 1, female donor and male recipient (n = 8); group 2, male donor and female recipient (n = 7); and group 3, male donor and male recipient (n = 21). The three groups were similar with regard to donor and recipient age, weight, body surface area, serum lipids, left ventricular function, histocompatibility, cellular and vascular rejection, and cytomegalovirus infection. To precisely quantitate the extent of cardiac allograft vasculopathy, intravascular ultrasound was performed in all patients at the time of first annual angiography. Intimal thickening and intimal index were accurately quantitated by intravascular ultrasound. Intimal thickening was significantly greater in group 1 (0.55 +/- 0.15 mm) than in group 2 (0.18 +/- 0.04 mm) or group 3 (0.29 +/- 0.05 mm) (P < .05). In addition, the intimal index was greater in group 1 (0.20 +/- 0.04) than in group 2 (0.07 +/- 0.02) or group 3 (0.15 +/- 0.02) (P < .01, group 1 versus group 2)., Conclusions: Male recipients of female allografts have a higher degree of vascular intimal hyperplasia detected by intravascular ultrasound at 1 year after heart transplantation. These findings indicate that donor and recipient gender influences the early genesis of cardiac allograft vasculopathy.

Background: Aortic counterpulsation has been observed to reduce the rate of reocclusion of the infarct-related artery after patency has been restored during acute myocardial infarction in observational studies. To evaluate the benefit-to-risk ratio of aortic counterpulsation during the early phase of myocardial infarction, a multicenter randomized clinical trial was performed., Methods and Results: Patients who had patency restored during acute cardiac catheterization within the first 24 hours of onset of myocardial infarction were randomly assigned to aortic counterpulsation for 48 hours versus standard care. Intravenous heparin was used similarly in both groups and was continued for a median (25th, 75th percentile) of 5 (2,7) days. A total of 182 patients were enrolled; 96 were assigned to aortic counterpulsation and 86 to standard care. Repeat cardiac catheterization was performed at a median of 5 (4,6) days after randomization in 89% of patients assigned to aortic counterpulsation and in 90% of control patients. Patients randomized to aortic counterpulsation had similar rates of severe bleeding complications (2% versus 1%), number of units of blood transfused (mean, 1.3 +/- 2.6 versus 0.9 +/- 1.8 units), and vascular repair or thrombectomy (5% versus 2%) compared with patients treated in a conventional manner. Patients randomized to aortic counterpulsation had significantly less reocclusion of the infarct-related artery during follow-up compared with control patients (8% versus 21%, P < .03). In addition, there was a significantly lower event rate in patients assigned to aortic counterpulsation in terms of a composite clinical end point (death, stroke, reinfarction, need for emergency revascularization with angioplasty or bypass surgery, or recurrent ischemia): 13% versus 24%, P < .04., Conclusions: This randomized trial showed that careful use of prophylactic aortic counterpulsation can prevent reocclusion of the infarct-related artery and improve overall clinical outcome in patients undergoing acute cardiac catheterization during myocardial infarction.

Background: The pathological consequences of cardiovascular laser irradiation have been studied extensively in vitro. Previous in vivo studies of laser-induced injury have included analyses of acute and/or chronic findings in experimental animals. Little information, however, is available regarding the acute effects of laser irradiation of human vascular tissues in vivo., Methods and Results: To determine the acute pathology resulting from laser irradiation of human vascular tissue in vivo, specimens retrieved from 23 patients by directional atherectomy immediately after laser angioplasty (19 peripheral and four coronary) were examined by light microscopy. Of the 23 patients, three (13.0%) were treated with a metal-capped ("hot-tip") fiber coupled to a continuous-wave neodymium:yttrium-aluminum-garnet (Nd:YAG) laser using up to 18 W power and 18-305 seconds of cumulative exposure time; in all three patients (100%), thermal injury, including frank charring several cell layers thick, was seen along the luminal borders of the atherectomy specimen. In eight of the 23 patients (34.5%), laser angioplasty was performed using a 250-microseconds holmium:YAG laser at fluences up to 2,300 mJ/mm2, a repetition rate of 5 Hz, and 25-200 seconds of cumulative exposure; in seven of eight patients (85.5%), the atherectomy specimen showed signs of vacuolar injury consisting of central and satellite Alcian-blue-negative vacuoles. In two patients (25.0%), there was a "smudged" or "shredded" edge, whereas in one patient, frank signs of thermal injury were observed. Finally, in 12 of the 23 patients (52.2%), laser angioplasty was performed using a 120-nsec excimer laser at fluences up to 60 mJ/mm2, a repetition rate of 25 Hz, and a cumulative exposure time of 21-315 seconds. Pathological findings among these 12 patients were limited to nine patients (75%) in whom a weakly basophilic, smudged, and/or shredded appearance approximately one cell layer thick was observed along the luminal border of the atherectomy specimen and two patients (16.7%) with small foci of vacuolar injury. None of the atherectomy specimens retrieved after excimer laser angioplasty disclosed signs of thermal injury., Conclusions: These findings document that acute pathological alterations resulting from in vivo laser angioplasty are variable, depending on the laser source used, and are similar to that predicted by experimental studies performed previously in vitro. The prognostic implications of these varying pathological features remain to be clarified.