Partial left ventriculectomy: history, current status, and future role.

Whereas discouraging clinical results and lack of scientific evidence decreased the initial interest in partial left ventriculectomy (PLV), factors contributing to success and failure have now been identified by clinical observations, theoretical analyses, and data from an international registry, which are herein reviewed to outline the current status and future role of this procedure as a treatment of heart failure.

Perioperative hemodynamics in patients undergoing partial left ventriculectomy.

OBJECTIVES: Effects of partial left ventriculectomy (PLV) were studied by analyzing perioperative hemodynamics with measurements of left ventricular (LV) pressure-volume (PV) relationships and thermodilution catheter measurements in the pulmonary artery. METHODS: Between July and October 1996, 43 consecutive patients underwent PLV with and without mitral valvuloplasty with a thermodilution catheter and PV loop analysis immediately before and after surgery. Patients were 52+/-13 years and 67+/-13 kg, with reduced functional capacity (New York Heart Association 3.3+/-0.3) due to cardiomyopathy (24), ischemic disease (13), valvular disease (3), and Chagas' disease (3). RESULTS: PLV required cardiopulmonary bypass for 44+/-24 minutes, with the heart arrested in 10 patients for 26+/-22 minutes for coronary artery bypass grafting (8), aortic valve replacement (2), and autotransplantation (2). Two patients failed to come off bypass, six died in the hospital and 35 (35 [81.4%] of 43) were discharged. Changes in PV loops included decreased end-diastolic and end-systolic volume, resulting in no change in stroke volume. Pulmonary artery wedge pressure decreased despite elevated end-diastolic pressure. Ejection fraction, end-systolic elastance (E-max), afterload recruitable stroke work, and volume intercepts all improved and resulted in similar stroke work with less energy expenditure (less PV area), thus improving myocardial energetic efficiency. CONCLUSION: Results suggest that PLV improves systolic function but decreases diastolic compliance, which results in reduced net ventricular function immediately after surgery. Thus, immediate hemodynamic improvements appeared to derive from reduced severity in mitral regurgitation and perioperative load manipulation. Improved myocardial energetics may ameliorate LV function and improve the course of underlying myocardial disease.

Histopathology of resected myocardium and outcome of partial left ventriculectomy.

BACKGROUND: Since preoperative hemodynamics are not proven to be a predictor of effects of partial left ventriculectomy (PLV), myocardial histopathology may be better correlated with effects and outcome of PLV. METHODS: Myocyte size (micron) in the excised myocardium was measured in 338 patients undergoing PLV. Endocardial fibrosis, interstitial fibrosis, and inflammatory cell infiltration were enumerated as none = 0, mild = 1, moderate = 2, and severe = 3. These histopathologic observations were correlated with patients' postoperative survival. RESULTS: Reduced survival was seen in patients with advanced (> or = moderate) interstitial fibrosis in all patients (n = 338, p = 0.064) and in the subgroup with nonischemic etiology (n = 229, p = 0.0039). Although correlation between endocardial and interstitial fibrosis was significant (r = 0.55, p < 0.01), endocardial fibrosis failed to correlate with postoperative survival. While Chagas' disease was associated with severe inflammation and poor survival, the presence of inflammatory cell infiltration had no effect on survival in all patients combined (p = 0.943). Although most patients (n = 266, 79%) had myocyte diameter over 30 micron, those with less hypertrophy (< 30 micron, n = 70, 21%) had a tendency toward increased survival (p = 0.067) regardless of underlying etiology. CONCLUSION: Interstitial fibrosis may be an important factor in stratification of patients for repair (PLV) or replacement (transplantation). PLV may be more beneficial in patients with less hypertrophy, before develqpment of interstitial fibrosis. Endomyocardial biopsy might not predict the extent or variation in degree of interstitial fibrosis, which may be better evaluated by other metabolic or perfusion studies that measure overall myocardial histopathology and viability.

Does avoidance of cardiopulmonary bypass decrease the incidence of stroke in diabetics undergoing coronary surgery?

BACKGROUND: The adverse effects of diabetes mellitus on the coronary circulation and the higher incidence of cardiovascular events in diabetic patients are well documented [Johnson 1982]. Improvements in myocardial protection, revascularization techniques, and anesthetic management have had favorable impacts on coronary artery bypass grafting (CABG) outcome in diabetic patients. Despite that, diabetic patients are significantly more likely to have a prior history of myocardial infarction, congestive heart failure, peripheral vascular disease, and hypertension, as well as having a significantly greater baseline serum creatinine. The aim of our study was to record, compare, and analyze the stroke rate among patients with a history of preoperative diabetes undergoing "off-pump" CABG (OPCAB) with conventional cardiopulmonary bypass (CPB) CABG to determine whether the stroke rate in this higher risk population could be decreased by off-pump techniques. METHODS: The records of 1,227 patients with a pre-operative history of diabetes undergoing conventional CABG (973 patients, 79.3%) using cardiopulmonary bypass and off-pump CABG 254 (20.7%) were analyzed from 1995 through 1999. There were no differences in age, sex, or elective/urgent status of patients. Preoperative risk factors (gender distribution, carotid disease, ejection fraction, CHF, hypertension, previous MI) were identical in both groups. The goal of the operations were complete revascularization, which was achieved via median sternotomy in both groups. RESULTS: Our reported series reveals a stroke rate of 3.6% in the CPB group and 1.2% in the off-pump group. This evidence alone was not statistically significant, but two other high-risk criteria for stroke, re-do CABG and calcified aortas, revealed that the off-pump series had a higher percentage of each (26.4% redos in off-pump vs. 8.7% CPB redos, p < 0.005; 7.1% calcified aorta cases in the off-pump group vs. 2.9% in the CPB group, p < 0.004). The threefold reduction in stroke may be clinically significant in light of the higher-risk profile of the off-pump group. The limitations of this study are that it was retrospective, there were a small number of events, and different surgeons were involved in the two different approaches to these patients. CONCLUSIONS: Improvements in myocardial protection, revascularization techniques, and anesthetic management have made significant, favorable impacts on CABG outcome in diabetic patients. New diagnostic and therapeutic strategies must be developed to lessen the medical and economic implications of stroke. A larger series or a more effective way of analyzing preoperative risk may well have shown a statistically significant difference in the stroke incidence given the differences in preoperative risk factors/stroke predictors. Until such advances occur, a threefold reduction of stroke incidence using OPCAB certainly makes this technique a favorable one for high-risk diabetics requiring coronary revascularization.

Robotically assisted video-enhanced-endoscopic coronary artery bypass graft surgery.

Since 1988, through fierce industry-driven competition and patients' preference for minimally invasive procedures, widely diffused through the media, laparoscopic cholecystectomy was universally adopted and rapidly became the "gold standard" for symptomatic cholelithiasis. Robotically assisted video enhanced-endoscopic coronary artery bypass surgery (RAVE-CABG) will most likely follow suit with its similar developmental processes for symptomatic coronary artery disease. Since 1998, there are currently two surgical robotic systems that have been used in a clinical setting for endoscopic coronary artery bypass (ECABG): the da Vinci and the ZEUS system. Although each has separate learning curves to overcome, as with any new technology, both offer the promise to contribute in the interests of reduced hospital days, earlier return to normal activity, less pain, better cosmesis, and the rethinking of surgical dogma such as wide exposure.

On-pump and off-pump coronary artery bypass grafting in the elderly: predictors of adverse outcome.

OBJECTIVE: To establish the role that coronary artery bypass grafting (CABG) without cardiopulmonary bypass (CPB) may have in improving perioperative outcomes of patients 70 years of age and older. BACKGROUND: Coronary revascularization in elderly patients is associated with morbidity and mortality rates higher than those observed in younger patients. The impact of CABG without CPB on perioperative outcomes has not been clearly established. METHODS: This retrospective, nonrandomized study consisted of 1,872 CABG patients. Of these, 1389 underwent CABG with CPB (CPB group) and 483 patients underwent CABG without CPB (off-pump group). Preoperative variables and outcomes were compared between the two groups. Multivariate logistic regression analysis was used to identify independent predictors of mortality, stroke, and adverse outcome. RESULTS: Demographics, Canadian Cardiovascular Society staging, operative priority, and other preoperative variables were comparable between the two groups. The prevalence of previous myocardial infarction was higher in the CPB group (62.6% vs 56.7%; p < 0.005), whereas the prevalence of calcified aorta and preoperative renal failure were higher in the off-pump group (5.4% vs 9.5%; p = 0.04 and 1.7% vs 3.3%; p = 0.04, respectively). Although the graft/patient ratio was higher in the CPB group (3.4 vs 1.9), these patients displayed more extensive coronary artery involvement. At univariate analysis, patients in the off-pump group had a higher rate of freedom from complications (88.2% vs 81.3%; p < 0.005) and a lower incidence of stroke (2.1% vs 4.2%; p = 0.034) than patients in the CPB group. Although there was a trend for a higher actual mortality in the off-pump group (4.8% vs 3.7%; p = ns), the risk adjusted mortality in this group was lower (1.9% vs 2.1%). Multivariate analysis showed that while the use of CPB correlated independently with an increased risk of overall complications, it was not associated with a higher probability of death or stroke. CONCLUSIONS: This investigation suggests that elderly patients undergoing CABG may benefit from off-pump revascularization, as the use of CPB correlated independently with an increased risk of overall complications. However, CPB did not emerge as an independent predictor of death or stroke at multivariate analysis.

OPCAB therapy survey: off-pump clopidogrel, aspirin or both therapy survey.

BACKGROUND: Standards for heparinization during off-pump coronary artery bypass (OPCAB) are lacking. Similarly, there are no established standards for antiplatelet therapy before or after OPCAB. The aim of this study was to determine current practices and standards for both antiplatelet and heparin therapy in OPCAB. METHODS: A postal, multiple-choice survey questionnaire was sent to 800 randomly chosen cardiothoracic surgeons in the United States and Canada. Responses were tabulated and analyzed. RESULTS: The overall response rate was 38% (304 surgeons). The respondents performed CABG in centers with an overall volume between 240 and 1,250 procedures per year (average 380 procedures per year). OPCAB procedures within the same institutions ranged from 20 and 375 cases per year. Sixteen percent (48) of the respondents routinely administer antiplatelet therapy preoperatively; of these, 18% (9) use clopidogrel (Plavix) and 65% (31) aspirin. Eighty-eight percent (267) of the respondents routinely administer antiplatelet therapy after OPCAB. Of these, 24% (65) use clopidogrel and 74% (197) aspirin. Anticoagulation protocols during OPCAB were more variable with 28% (85) administering full dose of heparin, 54% (164) administering half dose heparin, and 13% (40) administering 1/3 dose of heparin during construction of coronary anastomoses. Although 10% (30) maintain an activated clotting time (ACT) above 400 seconds, 70% (213) are content with an ACT above 300 seconds and less than 400 seconds, and 20% (61) responded as "other". The average blood shed postoperatively was 600 ml (range 300 ml and 1 liter). Forty percent (122) administer protamine at half dose, and 60% (182) administer a full dose. CONCLUSION: Although the vast majority of surgeons use antiplatelet therapy postoperatively, a minority administer preoperative antiplatelet agents for OPCAB. The majority of surgeons use a half dose of heparin during OPCAB with ACT maintained above 300 seconds (> 80%). Prospective studies are necessary to determine the short and intermediate effects of antiplatelet therapy and heparinization doses in OPCAB surgery.

Mitral regurgitation after partial left ventriculectomy as the cause of ventricular redilatation.

BACKGROUND: It remains unclear whether ventricular redilatation after partial left ventriculectomy (PLV) is due to underlying pathology or to continued volume overload amenable to surgery. METHODS: Among patients undergoing PLV, 32 had Doppler echocardiography preoperatively, immediately after surgery (< 1 week), early after surgery (1-3 months), and late after surgery (8-14 months). Patients were divided into groups with mitral regurgitation (MR; MR+, n = 16) and without postoperative MR (MR-, n = 16) and were compared for ventricular size, performance, and survival. RESULTS: After initial surgical reduction, left ventricular dimension on average gradually increased back to the preoperative level in subgroups of patients with valvular disease and cardiomyopathy and in all patients combined. Most patients showed drastically reduced left ventricular dimension early after PLV. In MR+ patients, dimension increased back to the preoperative level within 3 months after surgery, whereas the MR- group maintained reduced dimension throughout the first year in all patients combined and in a subgroup of patients with cardiomyopathy. Occurrence of significant MR after PLV appeared to be related to severity of fibrosis in excised myocardium but not to severity of preexisting MR, etiology, or performance of mitral valvuloplasty. CONCLUSIONS: Early postoperative MR, residual or new, appeared to play an important role in dictating early hemodynamics and late outcome in patients undergoing PLV. Results suggest an aggressive simultaneous approach to abolish MR. Causative role of myocardial fibrosis remains unclear and needs further study.

Transventricular mitral annuloplasty in a patient undergoing partial left ventriculectomy.

A 70-year-old male patient with heart failure resulting from dilated cardiomyopathy underwent a partial left ventriculectomy between the papillary muscles and a newly devised transventricular mitral annuloplasty. Intraoperative transesophageal Doppler echocardiography revealed reduced ventricular dimensions and corrected mitral insufficiency with unchanged ventricular filling patterns, allowing prompt recovery despite unchanged myocardial pathology.

Exposure and mechanical stabilization in off-pump coronary artery bypass grafting via sternotomy.

Although off-pump coronary artery bypass grafting (CABG) is gaining popularity, obtaining exposure and stabilization of coronary arteries located on the lateral and inferior wall of the heart may be problematic. The aim of this study is to describe strategies and techniques of coronary exposure and mechanical stabilization that may be used to achieve total myocardial revascularization of the beating heart.

Aortobronchial fistula after endovascular stent graft repair of the thoracic aorta.

Endovascular stent graft repair of descending thoracic aortic aneurysms has been recently introduced as an alternative to conventional graft replacement of the diseased aorta. As experience with this new technique accumulates, complications may occur. We herein report the case of a patient in whom we observed distal migration with leak of an endovascular stent graft previously inserted in the descending thoracic aorta, associated with an aortobronchial fistula. The urgent surgical treatment undertaken, which consisted of graft replacement of the previously stented aorta, had a fatal outcome.