Shuli Silberman

Repair of Ischemic Mitral Regurgitation: Comparison Between Flexible and Rigid Annuloplasty Rings

BACKGROUND The surgical treatment of ischemic mitral regurgitation (MR) usually involves implantation of an annuloplasty ring. We compared results of mitral valve repair using a flexible or a rigid annuloplasty ring in patients with ischemic MR undergoing coronary artery bypass graft surgery. METHODS There were 169 patients. A flexible ring was implanted in 117 and a rigid ring in 52. Age and clinical profile, degree of left ventricular dysfunction, and degree of MR (mean 3.2) were similar between groups. RESULTS Operative mortality was 9% in each group. Follow-up (58 +/- 30 months for flexible group and 14 +/- 7 months for rigid group) was available for 91%. For the flexible and rigid ring groups, respectively, mean New York Heart Association functional class was 1.9 and 1.6, with 33% and 14% in classes III to IV (p = 0.03); mean MR grade was 1.25 and 0.7 (p = 0.006). There was no difference in left ventricle function or dimensions. At follow-up, 29 patients (34%) in the flexible group had residual MR of moderate degree or greater compared with 6 (15%) in the rigid group (p = 0.03). Mean tricuspid incompetence gradient was 39 and 34 mm Hg (p = nonsignificant); however, the degree of reduction was greater in the rigid group (p = 0.001). Late mortality was observed in 32 patients, all in the flexible group. CONCLUSIONS Clinical and hemodynamic results are better with rigid mitral annuloplasty rings compared with flexible rings. That result may be due to ring design, which dictates not only the annular diameter but also annular configuration. Longer follow-up is needed to determine differences in survival.

Exercise hemodynamics of aortic prostheses: comparison between stentless bioprostheses and mechanical valves

BACKGROUND Nonstented bioprostheses have been associated with lower resting gradients than stented bioprostheses or mechanical valves. We compared the hemodynamic performance of nonstented bioprostheses and mechanical valves with normal native aortic valves at rest and exercise. METHODS Dobutamine echocardiography was used to assess gradients and effective orifice area index at rest and exercise in patients with the Toronto stentless porcine valve (TSPV; n = 13; mean implant size 25.7 mm), Medtronic Freestyle (FR; n = 11; mean implant size 23.9 mm), Sorin Bicarbon (SOR; n = 11; mean implant size 24.5 mm), St. Jude Medical (SJM; n = 10; mean implant size 21.3 mm), and normal native aortic valves (NOR; n = 10). RESULTS All groups demonstrated a major rise in cardiac output at maximal dobutamine infusion. At rest and exercise, respectively, mean gradients were 5.48 +/- 1.1 mm Hg and 5.83 +/- 0.9 mm Hg for TSPV, 5.68 +/- 1.2 mm Hg and 7.50 +/- 1.7 mm Hg for FR, 10.29 +/- 1.4 mm Hg and 20.78 +/- 2.7 mm Hg for SJM, 5.26 +/- 0.8 mm Hg and 11.1 +/- 1.8 mm Hg for SOR, and 1.54 +/- 0.4 mm Hg and 2.18 +/- 0.7 mm Hg for NOR. In comparison with normal valves, both stentless groups showed no change in mean gradient at exercise, whereas both mechanical groups showed an increase in gradient at exercise (p < 0.04). CONCLUSIONS Stentless valves behave similarly to normal aortic valves in that there is almost no increase in gradient at exercise. Both mechanical valve groups showed increased gradients at exercise, suggesting that these valves obstruct blood flow. Our data add further evidence that stentless valves are hemodynamically superior to mechanical valves in the aortic position.

Mitral Valve Repair in Severe Ischemic Cardiomyopathy

Background: Patients with ischemic mitral valve insufficiency (MR) and poor left ventricular (LV) function present a high operative risk. Whether to repair or replace these valves is controversial, while some suggest that heart transplant offers a better solution. We investigated our early and late results in this difficult subset of patients. Methods: Between 1993–1999, 115 patients underwent mitral valve repair (MVR) in our department. Twenty‐one patients had severe LV dysfunction with ejection fraction < 25%. Mean age was 60 years (range 45–81). Nineteen (90%) were in New York Heart Association (NYHA) Class IV, 7 (33%) underwent emergency surgery, 3 (14%) were in cardiogenic shock, and 2 (10%) were taken to the operating room under cardiopulmonary resuscitation. All underwent coronary artery bypass grafting (CABG) in addition to MVR, with a mean number of grafts 2.9 per patient. Results: There were no early operative deaths. The average stay in intensive care was 5.9 days (range 1–52). There were three late deaths (14%). Follow‐up evaluation up to 3 years showed marked improvement in clinical status. Twelve (67%) patients are in NYHA Class I‐II, and three (17%) in Class III. Echocardiography revealed good function of the mitral valve in all, although overall LV function did not change significantly. Conclusion: (1) MVR in patients with severe ischemic cardiomyopathy can be accomplished with excellent results. (2) There is marked symptomatic improvement in these patients, even though LV function did not seem to be improved. (3) Long‐term survival still needs to be defined.

Comparison of exercise hemodynamics among nonstented aortic bioprostheses, mechanical valves, and normal native aortic valves.

Abstract Background: While aortic valve prostheses are known to perform well at rest, few studies have examined them under stress. We compared stress hemodynamics of mechanical valves and nonstented porcine valves in the aortic position to that of normal native aortic valves. Methods: Dobutamine echocardiography was used to assess mean and peak gradients and effective orifice area index (EOAI) at rest and exercise in patients with the Toronto Stentless Porcine Valve (SPV) (n = 13, mean implant size 25.7 mm), Sorin Bicarbon mechanical valve (SOR) (n = 11, mean implant size 24.5 mm), and patients with normal native aortic valves (NOR) (n = 10). Dobutamine infusion was started at 5 µ/kg per minute, and increased by increments of 5 µ/kg per minute until the target heart rate was achieved or until a maximal dose of 40 µ/kg per minute. Results: At rest and exercise, respectively, cardiac output (L/min) was 5.2 and 10.4 for Toronto SPV; 7.4 and 13.5 for SOR; and 4.6 and 11.2 for NOR. Measured EOAI (cm2) was 1.1 ± 0.2 and 1.15 ± 0.2 for TORONTO SPV; 1.60 ± 0.3 and 1.58 ± 0.3 for SOR; and 1.45 ± 0.2 and 1.46 ± 0.2 for NOR. Mean gradients (mmHg) were 5.48 1±.1 and 5.83 ± 0.9 for TORONTO SPV; 5.26 ± 0.8 and 11.3 ± 1.8 for SOR; and 1.54 ± 0.4 and 2.18 ± 0.7 for NOR. Peak gradients (mmHg) were 11.9 ± 2.0 and 21.0 ± 3.7 for TORONTO SPV; 10.79 ± 1.7 and 25.9 ± 3.4 for SOR; and 2.38 ± 0.9 and 6.1 ± 2.3 for NOR. Conclusions: Although the mechanical group (SOR) had larger measured EOAI, the greater increase in gradients with exercise in this group suggests that the TORONTO SPV is less obstructive to flow.

Does coronary endarterectomy increase the risk of coronary bypass

Abstract  Background: With increased incidence of angioplasty and stent implantation, patients referred for coronary bypass (CABG) typically have more advanced and diffuse coronary disease. Thus, more patients may require endarterectomy in order to achieve complete revascularization. We compared our results in patients undergoing CABG with or without coronary endarterectomy. Methods: Between 1993 and 1999, 2372 patients underwent isolated CABG in our department. A retrospective analysis was performed to compare patients requiring coronary endarterectomy of the LAD (group 1, n #88), endarterectomy of arteries other than the LAD (group 2, n #143), to those not requiring endarterectomy (group 3, n # 2071). Patients undergoing CABG without the use of cardiopulmonary bypass were excluded. Group 1 had a higher incidence of proximal LAD stenosis (p #0.001) than group 3, while group 2 had a higher incidence of peripheral vascular disease (p #0.02), preoperative Ml (p # 0.03) and LV dysfunction (p = 0.001). Results: Operative mortality was 10% in group 1 (p < 0.001) and 4% in group 2 (p #IMS) compared to 3% in group 3. Incidence of perioperative Ml was 12% in group 1 (p # 0.001) and 8% in group 2 (p # 0.001) compared to 2% in group 3. Conclusions: Patients requiring endarterectomy of the LAD are at increased risk of operative mortality. This was not true for patients requiring endarterectomy of arteries other than the LAD. In both groups there was an increased risk of perioperative myocardial infarction.

Preoperative Hemoglobin and Outcomes in Patients with CKD Undergoing Cardiac Surgery

BACKGROUND AND OBJECTIVES Preoperative anemia adversely affects outcomes of cardiothoracic surgery. However, in patients with CKD, treating anemia to a target of normal hemoglobin has been associated with increased risk of adverse cardiac and cerebrovascular events. We investigated the association between preoperative hemoglobin and outcomes of cardiac surgery in patients with CKD and assessed whether there was a level of preoperative hemoglobin below which the incidence of adverse surgical outcomes increases. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS This prospective observational study included adult patients with CKD stages 3-5 (eGFR<60 ml/min per 1.73 m(2)) undergoing cardiac surgery from February 2000 to January 2010. Patients were classified into four groups stratified by preoperative hemoglobin level: <10, 10-11.9, 12-13.9, and ≥ 14 g/dl. The outcomes were postoperative AKI requiring dialysis, sepsis, cerebrovascular accident, and mortality. RESULTS In total, 788 patients with a mean eGFR of 43.5 ± 3.7 ml/min per 1.73 m(2) were evaluated, of whom 22.5% had preoperative hemoglobin within the normal range (men: 14-18 g/dl; women: 12-16 g/dl). Univariate analysis revealed an inverse relationship between the incidence of all adverse postoperative outcomes and hemoglobin level. Using hemoglobin as a continuous variable, multivariate logistic regression analysis showed a proportionally greater frequency of all adverse postoperative outcomes per 1-g/dl decrement of preoperative hemoglobin (mortality: odds ratio, 1.38; 95% confidence interval, 1.23 to 1.57; P<0.001; sepsis: odds ratio, 1.31; 95% confidence interval, 1.14 to 1.49; P<0.001; cerebrovascular accident: odds ratio, 1.31; 95% confidence interval, 1.00 to 1.67; P=0.03; postoperative hemodialysis: odds ratio, 1.38; 95% confidence interval, 1.11 to 1.75; P<0.01). Moreover, preoperative hemoglobin<12 g/dl was an independent risk factor for postoperative mortality (odds ratio, 2.6; 95% confidence interval, 1.1 to 7.3; P=0.04). CONCLUSIONS Similar to the general population, preoperative anemia is associated with adverse postoperative outcomes in patients with CKD. Whether outcomes could be improved by therapeutically targeting higher preoperative hemoglobin levels before cardiac surgery in patients with underlying CKD remains to be determined.

Safety and Tolerability Study of an Intravenously Administered Small Interfering Ribonucleic Acid (siRNA) Post On-Pump Cardiothoracic Surgery in Patients at Risk of Acute Kidney Injury

Introduction Patients undergoing on-pump cardiac surgery are at an increased risk of acute kidney injury. QPI-1002, a small interfering ribonucleic acid, is under clinical development for the prevention of acute kidney injury. The safety, tolerability, and pharmacokinetics of QPI-1002 was evaluated in this first-in-man, Phase 1 study of a small, interfering ribonucleic acid in patients at risk of acute kidney injury after on-pump cardiac surgery. Methods In this phase 1 randomized, placebo-controlled dose-escalation study, a single i.v. dose of QPI-1002 was administered in subjects undergoing on-pump cardiac surgery. Subjects received placebo (n = 4), or QPI-1002 in increasing doses of 0.5 mg/kg (n = 3), 1.5 mg/kg (n = 3), 5 mg/kg (n = 3), and 10 mg/kg (n = 3). Results A total of 16 subjects were enrolled in the study. The average maximum concentration and area under the curve from the time of dosing to the last measurable concentration of QPI-1002 were generally dose proportional, indicating that exposure increased with increasing dose. The average mean residence time (mean residence time to the last measurable concentration) was 10 to 13 minutes in all 4 drug-dosing cohorts. Adverse events occurred at a similar rate in all study groups. Of the total 109 reported adverse events, the events were distributed as 26 in the placebo group and 21, 19, 24, and 19 in the QPI-1002 0.5, 1.5, 5.0, and 10.0 mg/kg groups, respectively. Eight of the 16 subjects experienced at least 1 serious adverse event: 4 (100%) in the placebo group and 4 (33.3%) in the combined QPI-1002 cohorts. Discussion QPI-1002 was rapidly eliminated from plasma. QPI-1002 was safe and well tolerated across all dose groups. Overall, no dose-limiting toxicities or safety signals were observed in the study. Further development of QPI-1002 for prophylaxis of acute kidney injury is warranted.

Buddy balloon for TAVI.

Percutaneous transfemoral aortic valve replacement is a new rapidly evolving technique that has made significant progress in recent years. The technology is however limitted and in some cases has resulted in failure to deliver the prosthetic valve. We describe a new technique using a buddy balloon, from the contralateral femoral artery, to assist in crossing the native aortic valve in those cases where extreme calcification and or tortuosity have caused the delivery system to hang up on the aortic wall. The technique is easily applied and facilitates the success of the procedure in cases which may otherwise have to be converted to open surgical aortic valve replacement.