Marc Sakwa

Hemodynamics and early clinical performance of the St. Jude Medical Regent mechanical aortic valve

BACKGROUND The St. Jude Medical Regent valve is the next-generation bileaflet aortic prosthesis, modified from the currently marketed St. Jude Medical mechanical valve to achieve a larger geometric orifice without changing the existing design of the pivot mechanism or blood-contact surface areas. The present study reports the hemodynamic and early clinical results of an ongoing multicenter trial investigating the performance of the Regent valve. METHODS Between July 1998 and July 2001, 361 patients at 17 centers in North America and Europe underwent implantation of a Regent mechanical aortic valve prosthesis. Clinical status was prospectively recorded, and echocardiography with Doppler was performed at discharge and at 2 months, 6 months, 1 year, and 2 years after operation. RESULTS Follow-up to date is 300 patient-years (average, 0.8 +/- 0.7 years per patient; range, 0.0 to 2.7 years). There were low rates of clinical adverse events. Mean gradient at 6 months was 9.7 +/- 5.3 mm Hg, 7.6 +/- 5.2 mm Hg, 6.3 +/- 3.7 mm Hg, 5.8 +/- 3.4 mm Hg, and 4.0 +/- 2.6 mm Hg, respectively, for 19-mm, 21-mm, 23-mm, 25-mm, and 27-mm valves; effective orifice area was 1.6 +/- 0.4 cm2, 2.0 +/- 0.7 cm2, 2.2 +/- 0.9 cm2, 2.5 +/- 0.9 cm2, and 3.6 +/- 1.3 cm2, respectively. Indexed effective orifice area was equal to or greater than 1.0 cm2/m2 for all valve sizes. Left ventricular mass index decreased significantly between early postoperative (165.9 +/- 57.1 g/m2) and 6-month follow-up (137.9 +/- 41.0 g/m2; delta = -28.0 +/- 49.1 g/m2; p < 0.0001). CONCLUSIONS The St. Jude Medical Regent aortic valve has excellent hemodynamics and early clinical results, with rapid and significant left ventricular mass regression. Long-term clinical assessment is ongoing.

St Jude Medical Epic porcine bioprosthesis: Results of the regulatory evaluation

BACKGROUND The St Jude Medical Epic heart valve (St Jude Medical, Inc, St Paul, Minn) is a tricomposite glutaraldehyde-preserved porcine bioprosthesis. The St Jude Medical Biocor porcine bioprosthesis is the precursor valve to the St Jude Medical Epic valve. The Epic valve is identical to the Biocor valve except that it is treated with Linx AC ethanol-based calcium mitigation therapy. METHODS The St Jude Medical Epic valve was implanted in 761 patients (mean age 73.9 ± 9.2 years) between 2003 and 2006 in the US Food and Drug Administration regulatory study in 22 investigational centers. The position distribution was 557 aortic valve replacements, 175 mitral valve replacements, and 29 double valve replacements. Concomitant coronary artery bypass grafting was performed in 50.8% of patients undergoing aortic valve replacement and 36.6% of those undergoing mitral valve replacement. RESULTS The early mortality was 3.6% in aortic and 2.3% in mitral valve replacement. The follow-up was 1675.5 patient-years with a mean of 2.2 ± 1.2 years/patient. Late mortality was 5.2%/patient-year in aortic and 6.6%/patient-year in mitral valve replacement. The late major thromboembolism rate was 0.98%/patient-year for aortic and 2.6%/patient-year for mitral valve replacement. There were 19 reoperations, including 2 for structural valve deterioration, 1 for thrombosis, 9 for nonstructural dysfunction, and 7 for prosthetic valve endocarditis. The actuarial freedom from reoperation owing to structural valve deterioration for aortic valve replacement at 4 years for age 60 years or less was 93.3% ± 6.4%; for ages 61 to 70 years, 98.1% ± 1.9%; and for older than 70 years, 100% (P = .0006 > 70 vs ≤ 60 years). There were no events of structural deterioration with mitral valve replacement. The actuarial freedom from major thromboembolism for all patients at 4 years was 93.6% ± 1.0%. The 2 cases of structural valve deterioration occurred in aortic valves that became perforated without calcification causing aortic regurgitation. CONCLUSIONS The performance of the St Jude Medical Epic porcine bioprosthesis is satisfactory at 4 years for both aortic and mitral valve replacement. This study establishes the early clinical performance including durability of this porcine bioprosthesis.

Repair of a coronary pseudoaneurysm with percutaneous placement of a saphenous vein allograft attached to a biliary stent

Late coronary artery pseudoaneurysm formation is a rare complication of perforation following percutaneous intervention. While surgical intervention is the treatment of choice for large expanding pseudoaneurysms, the optimal treatment strategy for small-to-moderate pseudoaneurysms is unclear. We describe the percutaneous placement of a saphenous vein allograft for treatment of a coronary artery pseudoaneurysm presenting as a late complication of coronary perforation.

Coronary artery bypass grafting with a minimized cardiopulmonary bypass circuit: A prospective, randomized trial

OBJECTIVE The study was designed to determine differences in blood loss and transfusion associated with a minimized cardiopulmonary bypass circuit versus a standard bypass circuit. METHODS From February 2005 through April 2006, 199 patients were randomized to undergo coronary artery bypass grafting with a standard cardiopulmonary bypass circuit (Medtronic, Inc., Minneapolis, Minn) or a minimized bypass circuit, the Medtronic Resting Heart Circuit. Laboratory perimeters (hemoglobin and platelet count), were measured at baseline, after initiation of cardiopulmonary bypass, and on intensive care unit admission. Lowest values recorded were noted. Blood administration was controlled by study-specific protocol orders, (transfusion for hemoglobin <8mg%). Patient demographic data were retrieved from the Society of Thoracic Surgeons database. Blood product administration was recorded during hospital admission, and chest tube drainage as total output collected from operating room to discontinuation. Continuous variables were tested with a Wilcoxin rank test, and categoric variables with X(2) and Fishers exact tests. RESULTS Hematocrit, equivalent at baseline, was higher in minimized circuit cohort at lowest point during cariopulmonary bypass (31.5% +/- 3.9% vs. 25.5% +/- 3.7%), after protamine (31.6% +/- 3.9% vs 29.2% +/- 3.7%), and on intensive care unit arrival (35.2% +/- 4.1% vs 31.8% +/- 3.5%, P < .001). Similarly, platelet count was higher in minimized circuit group on intensive care unit arrival, as was lowest platelet count recorded (170 x 10(3) +/- 48 cells/mm(3) vs 107 x 10(3) +/- 28 cells/mm(3), P < .0001). Time to extubation was shorter in minimized circuit group (848 +/- 737 minutes vs. 526 +/- 282 minutes, (P < .01), and total chest tube drainage was lower (1124 +/- 647 mL vs. 506 +/- 214 mL, P < .01). Fewer red blood cells (148 vs 19 units) were given in minimized circuit group (P < .0001). CONCLUSIONS A minimized cardiopulmonary bypass circuit provides less hemodilution, platelet consumption, chest tube output and lower post-operative blood loss than standard cardiopulmonary bypass. Red blood cell usage was also less. All differences are advantageous.

Intraoperative angiography to assess graft patency after minimally invasive coronary bypass

BACKGROUND Intraoperative angiography was performed to confirm graft patency immediately after minimally invasive coronary bypass operations. METHODS In 26 patients who had internal mammary artery grafting, intraoperative coronary angiography was performed with a portable digital fluoroscope. RESULTS High-resolution angiograms were obtained in all cases. Angiography documented vasospasm of the graft or native vessel in 9 patients (graft in 3, native in 2, graft and native in 4 others), which responded promptly to intracoronary vasodilators in all. Angiography identified technically unsuspected and clinically silent fixed stenoses (>50%) in 11 patients, attributable to graft kinking in 2, anastomotic obstruction in 6 (total occlusion in 4), and stenosis of the left anterior descending artery just distal to the anastomosis in three cases (total occlusion in one). In 9 of 11 patients, fixed stenoses were sufficiently severe to warrant intraoperative intervention by surgical revision (n = 5) or angioplasty via the graft (n = 4). CONCLUSIONS Intraoperative angiography after minimally invasive coronary artery bypass operations can immediately identify dynamic and fixed obstructions and facilitate their prompt treatment, thereby ensuring that each patient leaves the operating room with an optimal surgical result.

The role of temporary biventricular pacing in the cardiac surgical patient with severely reduced left ventricular systolic function

OBJECTIVE The objective was to evaluate the effects of atrial synchronous biventricular pacing in postoperative patients with severe cardiomyopathy. METHODS Atrial synchronous biventricular pacing epicardial leads were placed during cardiac surgery in patients with an ejection fraction of 30% or less. Patients were randomized to usual care pacing, the mode determined by the surgeon (excluding atrial synchronous biventricular pacing) with a preference for no pacing or atrial pacing (atrial inhibited pacing); atrial synchronous right ventricular pacing; or atrial synchronous biventricular pacing. Pacing was continued until cessation of hemodynamic support. At 12 hours postoperatively, patients were randomly tested in each mode (atrial inhibited, atrial synchronous right ventricular, and atrial synchronous biventricular pacing), and thermodilution outputs were measured. RESULTS Forty subjects were randomized. Groups were similar in age (66 +/- 11 years), gender (85% were male), ejection fraction (23% +/- 6%), QRS duration (111 +/- 30 ms), and surgical indication. There was no difference in stroke index or cardiac index at 12 hours, duration of inotropic or intra-aortic balloon pump support, intensive care unit, or hospital length of stay. On comparative crossover testing, stroke volume was similar with atrial inhibited pacing and atrial synchronous biventricular pacing (59.3 +/- 13.4 vs 57 +/- 12.1, respectively, P = not significant); however, atrial synchronous right ventricular pacing was inferior (56 +/- 12.9, P < .05 for comparison with atrial inhibited pacing). When compared with atrial inhibited pacing, atrial synchronous biventricular pacing showed a positive response in 17% of subjects (increase in stroke volume >or= 5%), whereas 41% had a 5% or greater decrease in stroke volume. CONCLUSION Pacing mode affects stroke volume in patients with severe cardiomyopathy. Atrial synchronous biventricular pacing was helpful in a minority, but in 41% it compromised stroke volume.

Acute occlusion of a left internal mammary artery graft immediately after redo coronary artery bypass surgery: Successful rescue PTCA

A patient with a patent left internal mammary artery (LIMA) to the left anterior descending (LAD) artery required repeat bypass grafting to the distal right coronary artery (RCA). Intraoperative injury to the LIMA resulted in acute anterior myocardial infarction, which was managed by successful rescue percutaneous transluminal coronary angioplasty (PTCA).

CARDIORESPIRATORY FITNESS AND SHORT TERM OUTCOMES WITH CORONARY ARTERY BYPASS GRAFT SURGERY

Pre-operative risk assessment for coronary artery bypass surgery (CABG) has been evaluated with multiple predictive models; yet none incorporate low cardiorespiratory fitness as a risk factor. The present study evaluates pre-operative metabolic equivalents (METs) and short term morbidity and