Hratch L. Karamanoukian

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 1872 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.

Factors affecting ventricular function and survival after partial left ventriculectomy.

Abstract Background: Partial left ventriculectomy (PLV) helps some patients but is deleterious in others. Selection of patients who will benefit from PLV, and exclusion of those who will not is necessary for safe and effective application of the procedure.

Transeventricular Mitral Annuloplasty in a Patient Undergoing Partial Left Ventriculectormy

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.

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.

Perioperative hemodynamics in patients undergoing partial left ventriculectomy.

Objectives: Effects of partial left ventriculectomy (PLV) were studied by analyzing porioperative 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), ischomic 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.

Does Repair of Mitral Regurgitation Eliminate the Need for Left Ventricular Volume Reduction

Abstract Background: Effects of partial left ventriculectomy (PLV) remain ill‐defined because mitral regurgitation (MR) repair by isolated annuloplasty alone has been reported to improve patients with dilated left ventricle and severe MR.

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 (μ) 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 histopethologic observations were correlated with patients postoperative survival. Results: Reduced survival was seen in patients with advanced (≥ 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 μ, those with less hypertrophy (> 30 μ, 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 development 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.

Use of the “Single Suture” Technique to Expose the Anterior Surface of the Heart

Abstractu2002 The “single suture” technique, which consists of placing a suture in the oblique sinus of the posterior pericardium and connecting it to a vaginal tape, is commonly adopted in off‐pump coronary artery revascularization to obtain elevation of the heart and coronary artery exposure. This report describes the use of this technique to expose the anterior wall of the heart in the setting of ventricular aneurysm repair.

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.

Techniques of Exposure and Stabilization in Off‐Pump Coronary Artery Bypass Graft

Abstract Recent advances in techniques of coronary artery exposure and myocardial stabilization in off‐pump myocardial revascularization have provided cardiac surgeons with a wide variety of new devices and techniques. Until recently, the main obstacle to performing complete myocardial revascularization without using cardiopulmonary bypass (CPB) has been the technical difficulties of exposing and stabilizing coronary targets, especially those located on the lateral and inferior wall of the heart. The extraordinary cardiac tolerance to nonconstrictive anterior elevation and lateral displacement, however, has allowed the development of new strategies of coronary exposure. These advances, in combination with the development of new techniques of mechanical myocardial stabilization, have impacted on the feasibility and safety with which coronary anastomoses on the beating heart can be constructed. The aim of this article is to describe the technical aspects involved in off‐pump coronary revascularization, focusing primarily on the most recent strategies of cardiac elevation and coronary exposure, the various techniques of myocardial stabilization, and some of the technical details of constructing distal anastomoses on the beating heart.