Search

Enterobacter cloacae are a rare cause of infective endocarditis (IE). We present an interesting case of a 51-year-old intravenous drug user with E. cloacae IE of a prosthetic aortic valve and a fistula into the right ventricle. He underwent surgical repair and 6 weeks of intravenous meropenem.

Background The Freestyle stentless bioprosthesis (FSB) has been demonstrated to be a durable prosthesis in the aortic position. We present data following Freestyle implantation for up to 10 years post-operatively and compare this with previously published results. Methods A retrospective cohort analysis of 237 patients following FSB implantation occurred at five Australian hospitals. Follow-up data included clinical and echocardiographic outcomes. Results The cohort was 81.4% male with age 63.2±13.0 years and was followed for a mean of 2.4±2.3 years (range 0-10.9 years, total 569 patient-years). The FSB was implanted as a full aortic root replacement in 87.8% patients. The 30-day all cause mortality was 4.2% (2.0% for elective surgery). Cumulative survival at one, five and 10 years was 91.7±1.9%, 82.8±3.8% and 56.5±10.5%, respectively. Freedom from re-intervention at one, five and 10 years was 99.5±0.5%, 91.6±3.7% and 72.3±10.5%, respectively. At latest echocardiographic review (mean 2.3±2.1 years post-operatively), 92.6% had trivial or no aortic regurgitation. Predictors of post-operative mortality included active endocarditis, acute aortic dissection and peripheral vascular disease. Conclusions We report acceptable short and long term outcomes following FSB implantation in a cohort of comparatively younger patients with thoracic aortic disease. The durability of this bioprosthesis in the younger population remains to be confirmed.

Background In the era of TAVI, there has been renewed interest in the outcomes of conventional AVR for high-risk patients. This study evaluates the short- and long-term outcomes of AVR in octogenarians. Methods A retrospective review was performed of all 117 patients aged ≥80 years who underwent AVR, (isolated AVR (n = 60) or AVR + CABG (n = 57),) from August 2005 to February 2011 at Royal Prince Alfred Hospital and Strathfield Hospital. Univariate analysis was used to compare pre- and post-operative variables between younger and older subgroups (age 80–84, n = 82; age 85–89, n = 35 respectively). Long-term survival data was obtained from the National Death Index at the Australian Institute of Health and Welfare and survival curves were constructed using the Kaplan–Meier method. Results The median age was 83 years (interquartile range, 81–85 years), 46.2% were females, the median EuroSCORE was 10.89% (interquartile range, 8.20–16.45%) and 16.2% of patients had a EuroSCORE ≥20%. The difference between subgroups for history of stroke was significant (p = .042). Post-operative complications included pleural effusion (12.8%), new renal failure (4.3%) and respiratory failure (4.3%). The rate of major adverse events was extremely low, with no cases of stroke. The 30-day mortality rate was 3.4%. There was a significant difference between subgroups for 30-day mortality (p = .007). 38.9% of patients were discharged home, 11.5% were transferred to another hospital and 38.9% spent a period of time in a rehabilitation institution post discharge. In terms of long-term survival, the six-month, one-year and three-year survival was 95.6%, 87.6% and 58.4% respectively. Conclusions Surgical AVR yields excellent short- and long-term outcomes for potentially high-risk, elderly patients.

Background Aortic arch replacement is a potentially high-risk operation and in the re-operative setting has been found to be a risk factor for poor outcome, yet there is a dearth of published data specifically on this topic. The aim of the study was to review our unit's outcomes in this re-operative setting. Method Data were collated for all patients who underwent aortic arch replacement surgery after previous cardiac surgery from January 1988 to November 2011. The patients were divided based primarily on elective versus non-elective and also early (≤2005) and late (≥2006) series. Results Twenty-seven eligible patients (22 male; median age: 53.0 years; elective: 14, non-elective: 13) were identified. There was a mean period of 14.5 years between the first operation and the subsequent aortic arch replacement. The overall 30-day mortality rate was 22.2% – 0% elective and 46.2% non-elective (P = 0.004). Overall permanent neurological dysfunction was 21.7% – 28.6% elective and 11.1% non-elective (P = 0.463). There were 11 early-series patients and 16 late-series patients. For early-series patients, 90.9% were non-elective versus 18.8% in the late-series patients. The 30-day mortality rate was 54.5% early series versus 0% late series. Conclusion Aortic arch replacement is high risk in the re-operative setting. These risks are even greater for non-elective procedures. This highlights the need for aggressive first-time surgery to reduce re-operative procedures and good long-term follow-up programmes to allow elective procedures if required.

The effects of off-pump coronary artery bypass (OPCAB) surgery on endothelial cell activation are poorly understood. Endothelial cell adhesion molecules (CAMs) are expressed and released when the endothelium is activated. We compared plasma CAMs (E-selectin, ICAM-1 and VCAM-1) and HUVEC expression of the same CAMs when exposed to plasma taken before, during and after OPCAB or on-pump coronary surgery (CABG).Patients undergoing first time CABG (n=10) or OPCAB (n=10) had 6 blood samples taken before surgery and up to 24h post-operatively. Plasma samples were assayed for E-selectin, ICAM-1 and VCAM-1. The same plasma samples were exposed to HUVEC cultures and cell-surface expression of E-selectin, ICAM-1 and VCAM-1 measured. Data are expressed as mean+/-SEM of n subjects.Plasma E-selectin was unchanged. Plasma ICAM-1 and VCAM-1 were elevated 24h post-operatively in both groups (P0.01), with no differences between the groups. Twenty-four hours post-OPCAB plasma increased basal and IL-1beta induced expression of endothelial VCAM-1 by 133+/-16% and 140+/-27% (P0.05), respectively. Plasma taken 3h post-CABG decreased endothelial VCAM-1 expression by 76+/-10% (P0.05). Peri-operative plasma had no effect on endothelial expression of E-selectin or ICAM-1 in either group.OPCAB and CABG with CPB appear to generate qualitatively different inflammatory responses with respect to endothelial activation, which may have clinical implications.

We report the first Australian use of the Impella ® LP 5.0, a minimally invasive, high-output left ventricular assist device. The device was inserted intra-operatively for cardiac failure following coronary artery grafting. Although it facilitated a temporary post-operative recovery, the patient ultimately succumbed due to left ventricular failure more than 30 days after the original procedure. This device has several advantages over existing forms of left ventricular support, and has the potential for widespread use in Australian centres.

Aortic arch replacement is a potentially high-risk operation and in the re-operative setting has been found to be a risk factor for poor outcome, yet there is a dearth of published data specifically on this topic. The aim of the study was to review our unit's outcomes in this re-operative setting.Data were collated for all patients who underwent aortic arch replacement surgery after previous cardiac surgery from January 1988 to November 2011. The patients were divided based primarily on elective versus non-elective and also early (≤2005) and late (≥2006) series.Twenty-seven eligible patients (22 male; median age: 53.0 years; elective: 14, non-elective: 13) were identified. There was a mean period of 14.5 years between the first operation and the subsequent aortic arch replacement. The overall 30-day mortality rate was 22.2% - 0% elective and 46.2% non-elective (P = 0.004). Overall permanent neurological dysfunction was 21.7% - 28.6% elective and 11.1% non-elective (P = 0.463). There were 11 early-series patients and 16 late-series patients. For early-series patients, 90.9% were non-elective versus 18.8% in the late-series patients. The 30-day mortality rate was 54.5% early series versus 0% late series.Aortic arch replacement is high risk in the re-operative setting. These risks are even greater for non-elective procedures. This highlights the need for aggressive first-time surgery to reduce re-operative procedures and good long-term follow-up programmes to allow elective procedures if required.

Persistent alteration to host polymorphonuclear cell (PMN) physiology has been demonstrated after cardiac surgery performed with cardiopulmonary bypass (CPB). However, to date, PMN physiology and function beyond the first 24 h have not been investigated after cardiac surgery performed without CPB (off-pump coronary artery bypass grafting [OPCAB]). Blood samples of 15 patients were collected preoperatively and on days 1, 3, and 5 after OPCAB. Expression of CD11b, CD18, CBRM1/5, and CD62L were assessed by flow cytometry under resting conditions and after stimulation with formyl methionyl-leucyl-phenylalanine (fMLF), and respiratory burst activity was also measured. Under resting conditions, PMN CD11b, CBRM1/5, and CD62L expressions were minimally altered by surgery. Compared with the response of preoperative PMNs, PMNs assayed on days 3 and 5 after OPCAB demonstrated a significantly blunted increase in the expression of CD11b and CBRM1/5 after fMLF, significantly diminished shedding of CD62L in response to platelet-activating factor and fMLF, and diminished superoxide production after stimulation on day 3. The alteration of PMN function after OPCAB implies that cardiac surgical trauma without CPB directly modulates host PMN physiology.

A retrieval service was established in New South Wales to provide mobile extracorporeal membrane oxygenation support to patients with severe, acute cardiac or respiratory failure. This service has also retrieved four adult patients from Nouméa, New Caledonia to Sydney on extracorporeal membrane oxygenation support, which are the first international retrievals of this type from Australia. We discuss our experience with these patients, three of whom survived to hospital discharge. However, one patient referred from New Caledonia died before extracorporeal membrane oxygenation could be established.

To describe a technique for transapical wire-assisted endograft deployment under rapid ventricular pacing for a type B dissection involving the proximal left subclavian artery and extending to the aortic bifurcation.A 58-year-old man presented with a symptomatic thoracic aneurysm as a complication of a chronic type B dissection, with a short proximal neck in zone 1. After arch vessel debranching, the patient underwent endoluminal repair with deployment of a closed web, tapered Valiant thoracic endograft over a through-and-through wire from the left groin to the apex of the left ventricle, using rapid ventricular pacing to reduce cardiac output. The remaining dissected aorta was covered with a second Valiant endograft down to the distal third of the descending thoracic aorta and bare Z stents down to the aortic bifurcation to re-expand the true lumen. A freeflow Valiant endograft was deployed as a proximal extension to treat a proximal type I endoleak. The recovery was complicated by retrograde type A aortic dissection, considered secondary to the bare stent. The complication was repaired surgically; postoperative computed tomography after recovery was unremarkable.Transapical wire-assisted deployment with rapid ventricular pacing is feasible and may provide improved stability for stenting within the aortic arch. The use of a stent-graft with a proximal bare stent is associated with a higher risk of retrograde extension of the dissection and warrants lifelong imaging follow-up.

Background— Recent studies in infective endocarditis have suggested an association between surgery and reduced mortality. However, these studies did not account for survivor treatment selection bias, which is an underrecognized source of error in observational studies. Therefore, we sought to evaluate the effects of survivor bias on surgical outcomes in infective endocarditis. Methods and Results— We studied 223 patients admitted with left-sided infective endocarditis between 1996 and 2006 and compared all-cause mortality between surgically treated and medically treated patients using Cox regression analysis. Propensity scores were used to account for selection bias, and time-dependent analyses were performed to account for survivor bias. Compared with medical patients (n=161), surgical patients (n=62) had lower mortality during a median follow-up of 5.2 years (32% versus 51%; P =0.02) with an unadjusted hazard ratio of 0.54 (95% CI, 0.33 to 0.88, P =0.01). After adjustment for baseline differences in propensity for surgery and risk of mortality, there remained a significant benefit for surgery (hazard ratio, 0.50; 95% CI, 0.28 to 0.88; P =0.02). However, this was diminished after time-dependent analysis (hazard ratio, 0.77; 95% CI, 0.42 to 1.40; P =0.39). Conditional Kaplan–Meier analyses confirmed the effect of survivor bias because the apparent benefit of surgery was primarily attributable to excess mortality in the medical group during early hospitalization when surgery was not frequently performed. Conclusions— Survivor bias significantly affects the evaluation of surgical outcomes in infective endocarditis, and it should be considered in other areas of outcomes research where randomized controlled trials are not feasible. Survivor bias is not corrected by propensity analysis alone but may be reduced by time-dependent survival analysis.

Background With the increasing use of OPCAB, potentially devastating thromboembolic events, including graft thrombosis may become increasingly evident. We present a study of the quantitative and temporal differences of the coagulation system, fibrinolysis and platelet activation after coronary artery surgery with or without cardiopulmonary bypass. Methods Patients undergoing on-pump CABG ( n =10) or OPCAB ( n =10) had six blood samples taken before surgery and up to 24h post-operatively. Activation of the coagulation cascade (tissue factor pathway—factor VIIa), endothelial injury (von Willebrand Factor antigen), thrombin generation (prothrombin fragments FI+II), fibrinolysis (decreased plasminogen levels), fibrin degradation (D-Dimer), platelet counts and platelet activation (soluble P-selectin) were quantified. Results CABG caused earlier and more significant generation of thrombin, however OPCAB caused a late and sustained generation of thrombin. CABG caused intraoperative activation of fibrinolysis and fibrin degradation, however, at 24h these parameters were equally elevated in both groups. Platelet activation was significant in the CABG group, but did not occur in the OPCAB group. Conclusions Late thrombin generation and reduced fibrinolysis in the presence of intact, functioning platelets may contribute to adverse thromboembolic events after OPCAB surgery. Thromboembolic prophylaxis and anti-platelet therapy may need to be more aggressive after OPCAB surgery.

Dissection is the commonest acute catastrophe involving the aorta. Computed tomography (CT) is increasingly used in evaluating patients with suspected aortic dissection. Occasionally normal anatomic structures may be misconstrued as pathologic due of lack of familiarity with anatomical variations. In scanning two patients with suspected dissection, we encountered pitfalls that led to an erroneous diagnosis of dissection. The subsequent clinical course and evaluation confirmed that the CT findings were artefactual. This report illustrates these potential errors and discusses the mechanisms.

The study aim was to assess the risk of reoperation for patients with a failing stented tissue valve.Between 1980 and 1999, 259 patients (118 males, 141 females; mean age 60.1+/-15.4 years) underwent redo valve replacement to replace a failing stented tissue valve. Of these patients, 94 (36.3%) underwent redo aortic valve replacement (AVR), 105 (40.5%) redo mitral valve replacement (MVR), and 60 (23.2%) redo aortic and mitral valve replacement (DVR). Twenty patients (7.7%) had previous coronary artery bypass grafting (CABG); further CABG were performed in 32 cases (12.4%). Preoperatively, 216 patients (83.3%) were in NYHA functional class III or IV.The early mortality was (6.5%; n = 17), including three patients who had AVR, five DVR, and nine MVR. A higher preoperative NHYA status (p0.0004) and emergency surgery (p0.0001) were significantly associated with an increased risk of operative death (univariate analysis). Age at surgery (p = 0.45), previous CABG (p = 0.45), position of the valve replaced (p = 0.2), type of implant (p = 0.06) and presence of coronary artery disease (p = 0.51) were not associated with a significant risk of operative mortality. Including those patients who died, 88 (34.0%) experienced a peri- or postoperative complication, seven of which (2.7%) were permanent.A failing tissue valve can be replaced, with acceptable operative mortality and morbidity. The choice of valve is a balance of its advantages and disadvantages, and these must be discussed with the patient. It appears, however, that the trend towards reducing the age at which tissue valve implantation is performed may be justified.

Background . An aging population and prolonged survival of patients after cardiac operations has meant that composite aortic root replacement after previous cardiac operation is being performed with increasing frequency. Methods . From January 1979 to July 1999, 32 patients underwent "reoperative" composite replacement of the aortic root at our institution. Previous operations were 16 aortic valve replacement, 9 coronary artery bypass grafting, 5 repair aortic dissection, and 7 others. Indications for operation included ascending aortic aneurysm in 16 patients, ascending aortic dissections in 10 patients, and other in 6 patients. Results . The unit elective mortality was 3 of 26 (11.5%). One surgeon's elective mortality was 1 of 22 (4.6%). The unit emergent mortality was 6 of 6 (100%). There has been one late death. Morbidity was low. Conclusions . Reoperative aortic root replacement is a technically demanding procedure, but expertise in the area achieves low elective mortality. Consideration should be given to aortic root replacement at the initial procedure. Close follow-up of postcardiac operation patients is necessary to proceed with elective aortic root replacement if indicated. Emergent presentation in the reoperative setting has a very poor prognosis.

Bleeding after replacement of the aortic root continues to be a major surgical problem. We detail two reliable methods, which are quick and simple to perform, that minimize surgical bleeding after aortic root replacement.

Both administration of cardioplegic solution and blood reperfusion result in endothelial dysfunction. The transit rate of albumin microbubbles during myocardial contrast echocardiography may reflect endothelial injury. Accordingly, we performed myocardial contrast echocardiography in 12 dogs undergoing cardiopulmonary bypass and measured the myocardial transit rate of microbubbles injected into the aortic root during delivery of cardioplegic solutions containing arterial and venous blood and delivery of pure crystalloid cardioplegic solution. The myocardial transit rate of 99mTc-labeled red blood cells was measured and perfusates were sampled for biochemical analysis at each stage. The microbubble transit rate was markedly prolonged during delivery of crystalloid cardioplegic solution and improved significantly during infusion of blood cardioplegic solution (p < 0.001); venous compared with arterial blood in the solution resulted in a greater rate (p < 0.001). The microbubble transit rate did not correlate with pH, oxygen tension or carbon dioxide tension values, or K+ concentration. The red blood cell transit rate remained constant regardless of the cardioplegic perfusate infused. Myocardial contrast echocardiography was also performed in 12 patients undergoing coronary artery bypass who underwent sequential arterial and venous reperfusion after cardioplegic arrest. The microbubble transit rate was faster with venous than arterial blood reperfusion (p = 0.01), although this gain was diminished when arterial blood reperfusion preceded venous blood reperfusion (p = 0.05). Our results indicate that endothelial dysfunction after cardioplegic arrest may be ameliorated by reperfusion with venous rather than arterial blood. (J Therac Cardiovasc Surg 1997;113:1100-8)