Search PubMed⌕ Search

Biomedical subjects

Christopher M Feindel

Publications and source records attributed to Christopher M Feindel.

At least 19 recordsLinked to original sources
PubMed2006

Twenty-year results of the Hancock II bioprosthesis.

BACKGROUND AND AIM OF THE STUDY: The Hancock II bioprosthesis (HII) has several design features designed to increase its durability. The study aim was to determine very long-term outcomes for the HII valve in a large patient population. METHODS: Long-term follow up was obtained by mail and/or telephone questionnaire of patients undergoing HII valve replacement surgery between 1982 and 2001 (n = 1,569). Follow up was complete on 1,568 patients (99.9%), and ranged from 0 to 250 months. RESULTS: Isolated aortic valve replacement (AVR) was performed in 1,010 patients and mitral valve replacement (MVR) in 559. The average (+/- SD) age of patients was 67 +/- 11 years, and 65% were males. Long-term death occurred in 445 AVR patients and 275 MVR patients, of which 11% and 17%, respectively, were valve-related. Twenty-year freedom from thromboembolism (all results actuarial) was 79 +/- 3% after AVR and 83 +/- 3% after MVR; freedom from endocarditis was 91 +/- 5% and 85 +/- 5%, respectively. Twenty-year freedom from structural valve deterioration (SVD) was 73 +/- 16% and 39 +/- 9% in AVR patients aged > or = 65 years and < 65 years, respectively. Similarly, 20-year freedom from SVD was 59 +/- 11% and 27 +/- 9% in MVR patients aged > or = 65 years and < 65 years, respectively. When actual statistical techniques were applied (cumulative incidence), 20-year actual risk of SVD was 18 +/- 3% in all AVR patients and 23 +/- 3% in all MVR patients. Reoperation was required in 72 AVR patients, and was valve-related in 60. A total of 49 MVR patients underwent reoperation; 48 of these were valve-related. CONCLUSION: The Hancock II bioprosthesis continues to show very good long-term results and durability, particularly in patients aged over 65 years.

Aged↗
PubMed2006

Valve surgery in octogenarians: a safe option with good medium-term results.

BACKGROUND AND AIM OF THE STUDY: The number of octogenarians is increasing in industrialized societies, and many patients aged over 80 years have heart valve disease which is amenable to surgical treatment. The perioperative outcomes and long-term results in very elderly patients undergoing valve surgery were evaluated. METHODS: A retrospective analysis was conducted of 2,791 patients with long-term follow up, who underwent valve surgery between 1990 and 2002. Of these patients, 132 (68 males, 64 females) were aged over 80 years (mean age 82 +/- 2 years; range: 80-94 years). RESULTS: Ninety-five patients (71.9%) underwent aortic valve replacement, 36 (27.3%) mitral surgery, and one patient had double-valve surgery. Sixty-five patients (49.2%) required concomitant coronary artery bypass grafting. There were 11 (8.3%) redo procedures. Patients aged over 80 years were significantly more symptomatic preoperatively than their younger counterparts (NYHA class III-IV 90.9% versus 69.0%, p < 0.001), with more congestive cardiac failure, hypertension, peripheral vascular disease, obstructive pulmonary disease, and renal failure (all p < 0.05). Perioperative mortality did not, however, differ significantly between groups (< 80 years versus > or = 80 years, 2.9% versus 4.6%, p = 0.10). There was also no difference in the composite end point of in-hospital death, renal failure, stroke, low output state, myocardial infarction, or sternal wound infection (< 80 years versus > or = 80 years, 10.5% versus 11.4%, p = 0.8). The mean follow up period was 66 +/- 44 months (< 80 years) versus 61 +/- 37 (> or = 80 years). Late mortality was higher in the elderly group (10-year survival 37.9% versus 68.2%, p < 0.001) and preoperative atrial fibrillation (RR 2.75; CI: 1.44-5.23), coronary artery disease (RR 1.98; CI 1.12-3.52) and congestive cardiac failure (RR 2.13; CI: 1.10-4.11) were independent predictors of late mortality. The groups did not differ with respect to long-term valve-related events, with the exception of fewer reoperations among elderly patients. CONCLUSION: Valve surgery in selected octogenarians is associated with low morbidity and mortality. The outlook after surgery is very good, and surgery should not be denied to this group on the basis of age alone.

Age Factors↗
PubMed2005

Stentless aortic valves are hemodynamically superior to stented valves during mid-term follow-up: a large retrospective study.

BACKGROUND: Several studies have compared left venticular mass (LVM) regression and hemodynamic data for stentless versus stented aortic bioprostheses with conflicting results. The major limitations of these studies are their small sample size and short-term follow-up. We therefore compared midterm LVM regression, hemodynamic data, and survival in a large population of tissue aortic valve replacement (AVR) patients. METHODS: All patients undergoing tissue AVR at our institution between 1998 and 2001 were included (n = 737). Patients were divided into two groups according to type of bioprosthetic implanted: stentless patients (total n = 310) (Toronto SPV [St Jude Medical, St Paul, MN], n = 146 and Freestyle [Medtronic, Minneapolis, MN], n = 164) and stented patients (total n = 427) (Perimount [Edwards Life Sciences Inc, Irvine, CA], n = 291 and Mosaic [Medtronic], n = 136). RESULTS: The two groups of patients had similar preoperative transvalvular gradients and LVM index (130 +/- 47 vs 130 +/- 42 g/m2 for stentless versus stented valves, respectively). Predischarge echos revealed that stentless patients had significantly lower mean transvalvular gradients (11 +/- 5 vs 15 +/- 6 mm Hg, p < 0.001) and larger effective orifice areas (1.32 +/- 0.52 vs 1.22 +/- 0.48 cm2, p = 0.01). Follow-up echocardiograms were obtained in 99% of surviving patients 28 +/- 22 (range, 0-79) months postoperatively. Stentless patients had significantly lower LVM index during follow-up (100 +/- 32 vs 107 +/- 32 g/m2, p = 0.005) and stentless valves were an independent predictor of LVM regression. Furthermore, a higher proportion of stented patients had residual LV hypertrophy during follow-up (28% vs 18%, p = 0.001). Stentless valves were associated with improved midterm survival by univariate analysis, but not by multivariable analysis. CONCLUSIONS: Midterm follow-up in a large number of patients reveals that stentless bioprostheses are hemodynamically superior to stented valves.

Aged↗
PubMed2005

Cardiac allograft preservation using donor-shed blood supplemented with L-arginine.

BACKGROUND: Despite improved preservation techniques, myocardial and endothelial dysfunction persists after cardiac transplantation. L-arginine has been shown to decrease endothelial injury in several models of ischemia and reperfusion. We assessed the effects of L-arginine on allograft preservation in a porcine model of cardiac transplantation. METHODS: Orthotopic cardiac transplants were performed in Yorkshire pigs. Hearts were randomly arrested with high potassium cardioplegia with or without L-arginine at a dose of 2.5 mmol/liter (LARGlow) and 5.0 mmol/liter. Donor-shed blood was collected at the time of organ harvest and intermittently perfused throughout the storage period. Coronary endothelial function was assessed at baseline and after reperfusion by measuring the change in coronary blood flow after exposure to acetylcholine or nitroglycerin. Pressure-volume relationships before and after transplant were evaluated with conductance catheter measurements. Myocardial biopsy specimens were assessed for inflammatory markers of cellular injury. RESULTS: High-dose L-arginine uniformly resulted in ischemic contracture in all hearts, and there was no return of function in any hearts after storage. The low-dose L-arginine group had a greater ability to wean off cardiopulmonary bypass and displayed improved recovery of left ventricular function. Control animals had a 26% reduction in coronary flow compared with 13% for LARGlow. LARGlow resulted in decreased release of inflammatory cytokines compared with control. CONCLUSIONS: Low-dose L-arginine preserves myocardial and endothelial function and decreases endothelial injury when it is used as a supplement to intermittent donor blood perfusion. In contrast, high-dose L-arginine resulted in severe endothelial injury and an inability to recover ventricular function after 5 hours of global ischemia.

Animals↗
PubMed2005

Combined endothelial and myocardial protection by endothelin antagonism enhances transplant allograft preservation.

BACKGROUND: Endothelin is a potent inflammatory peptide associated with myocardial dysfunction, coronary vasculopathy, and reduced survival after cardiac transplantation. We hypothesized that endothelin antagonism during cardiac allograft storage would limit early endothelial dysfunction and improve myocardial performance after transplantation. METHODS: Porcine orthotopic transplantations (n = 16) were performed after 6 hours of ischemic storage. Intermittent donor blood perfusion (control, n = 8) was compared with donor blood perfusion enhanced with 100 micromol/L of an endothelin receptor blocker (n = 8). Left ventricular performance was assessed after caval occlusion with a Millar micromanometer and conductance catheter. Coronary endothelial function was assessed in vitro with a macrovascular tissue bath apparatus. Myocardial endothelin, tumor necrosis factor alpha, and transforming growth factor beta protein expression were determined. Oxidative stress was inferred on the basis of 8-isoprostane levels, and myocardial metabolism was inferred on the basis of the extraction or production of oxygen, acid, and lactate by the heart. RESULTS: Endothelial function was diminished 48 hours after transplantation but not earlier. Endothelin receptor blocker treatment during preservation limited coronary endothelial dysfunction 48 hours after reperfusion ( P = .001). Weaning from cardiopulmonary bypass and left ventricular performance after transplantation was improved in endothelin receptor blocker-treated hearts (P = .02). Myocardial endothelin expression was equivalent in both groups and increased during reperfusion after transplantation (P = .001). Tumor necrosis factor alpha levels decreased with endothelin receptor blocker treatment (P = .02), whereas transforming growth factor beta levels did not change (P = .86). 8-Isoprostane, oxygen, acid, and lactate levels were similar, suggesting that oxidative stress and metabolism were not important mechanisms of benefit. CONCLUSIONS: Endothelin accumulates during allograft storage and contributes to endothelial and myocardial dysfunction after transplantation. Endothelin blockade during allograft preservation limits endothelial injury and enhances ventricular recovery after transplantation.

Animals↗
PubMed2004

Aortic valve sparing operations: basic concepts.

Aortic valve sparing surgery offers a unique opportunity to save the normal aortic valve in patients who require surgery for aortic root disease such as aneurysms, annuloaortic ectasia or aortic dissection. The surgical anatomy of the aortic root and the basic concepts of aortic valve sparing surgery are reviewed to provide surgeons and cardiologists a better understanding of when such operations might be suitable.

Aortic Aneurysm↗
PubMed2004

Clinical outcomes after separate and composite replacement of the aortic valve and ascending aorta.

OBJECTIVES: We sought to compare the clinical profile and outcomes of operations for aortic valve disease and ascending aortic aneurysm in patients treated with aortic valve replacement and supracoronary replacement of the ascending aorta or composite replacement of the aortic valve and ascending aorta (Bentall operation). METHODS: From 1990 through 2001, 133 patients had aortic valve replacement and supracoronary replacement of the ascending aorta, and 452 patients had Bentall operations. Aortic valve replacement and supracoronary replacement of the ascending aorta was performed in patients who had aortic valve disease and dilation of the ascending aorta, whereas the Bentall operation was performed in patients with aortic root abnormality and ascending aortic aneurysm. Mean follow-up was 4.6 +/- 3.1 years and was 100% complete. RESULTS: Patients who had aortic valve replacement and supracoronary replacement of the ascending aorta were older (61 +/- 13 vs 52 +/- 16 years, P <.001) and more likely to have aortic stenosis, coronary artery disease, and mitral valve disease than those who had Bentall operations. The use of mechanical valves was equal in both groups (42% for aortic valve replacement and supracoronary replacement of the ascending aorta and 43% for the Bentall operation). Operative mortality was 5% for patients undergoing aortic valve replacement and supracoronary replacement of the ascending aorta and 4% for patients undergoing the Bentall operation (P =.45). Survival at 10 years was 57% +/- 8% for patients undergoing aortic valve replacement and supracoronary replacement of the ascending aorta and 74% +/- 4% for patients undergoing the Bentall operation (P =.04), but the type of operation had no effect on survival. Older age, moderate or severe left ventricular dysfunction, active endocarditis, previous cardiac surgery, and coronary artery disease were independent predictors of death. The freedom from reoperation at 10 years was 95% +/- 5% for patients undergoing aortic valve replacement and supracoronary replacement of the ascending aorta and 94% +/- 3% for patients undergoing the Bentall operation (P =.18). Reoperations were mostly because of tissue valve failure or endocarditis. The risk of valve-related complications was the same in both groups. No patient required reoperation for aortic root aneurysm after having aortic valve replacement and supracoronary replacement of the ascending aorta. CONCLUSIONS: Aortic valve replacement and supracoronary replacement of the ascending aorta and the Bentall operation provide comparable long-term results. The Bentall operation is more appropriate for patients with aortic root abnormality and a dilated ascending aorta, whereas aortic valve replacement and supracoronary replacement of the ascending aorta is a perfectly acceptable operation for patients with aortic valve disease, normal or mildly dilated aortic sinuses, and a dilated ascending aorta.

Aortic Aneurysm, Thoracic↗
PubMed2003

Mitral valve surgery in patients with extensive calcification of the mitral annulus.

OBJECTIVES: The objective of this work was to examine the clinical outcomes of mitral valve surgery in patients with extensive mitral annular calcification. METHODS: Mitral valve surgery was performed in 54 patients (28 men and 26 women, mean age 63 +/- 14 years) with mitral regurgitation and extensive mitral annular calcification. Most patients (78%) were in New York Heart Association classes III and IV, 14 had coronary artery disease, and 9 had prior mitral valve replacement in which the calcium bar was not removed. The calcium bar was excised and a new mitral annulus was created by suturing a strip of pericardium onto the endocardium of the left ventricle from lateral to medial fibrous trigones and to the endocardium of the left atrium. The mitral valve was repaired in 12 patients and replaced in 42. In 23 patients the intervalvular fibrous body was reconstructed and the aortic valve was also replaced. Mean follow-up was 4.1 +/- 3.7 years and was complete. RESULTS: There were 5 operative deaths and 11 late deaths. Five-year survival was 73 +/- 7%. Four patients needed reoperation and each survived. Freedom from reoperation at 5 years was 89 +/- 6%. Three patients had a stroke and 4 had anticoagulation-related hemorrhage, one of which was fatal. Five-year freedom from valve-related mortality or morbidity was 75 +/- 8%. Most survivors were in New York Heart Association functional classes II and III. CONCLUSIONS: Resection of the calcium bar and creation of a new annulus with pericardium provided good clinical results in patients with extensive calcification of the mitral valve.

Adult↗
PubMed2003

Skeletonization of bilateral internal thoracic artery grafts lowers the risk of sternal infection in patients with diabetes.

OBJECTIVE: Deep sternal wound infection is a dreaded complication of coronary artery bypass surgery, particularly in patients with diabetes. This study determines whether skeletonization of internal thoracic artery conduits compared with pedicled harvesting reduces the risk of deep sternal wound infection in patients with diabetes undergoing bilateral internal thoracic artery grafting. METHODS: We reviewed prospectively gathered data on all patients who have undergone coronary artery bypass grafting and received bilateral internal thoracic artery grafts at our institution since 1990. We compared patients with diabetes who received skeletonized (n = 79) versus conventional pedicled (n = 36) internal thoracic artery conduits. RESULTS: The proportion of patients taking insulin (19.0% vs 14.0% for skeletonized vs conventional grafts, respectively, P =.6) or oral hypoglycemic agents (68.4% vs 69.4%, P =.9), as well as the prevalence of type I diabetes (2.5% vs 8.3%, P =.18), were similar in both groups. Patients who received skeletonized grafts were more likely to receive a free rather than an in situ right internal thoracic artery graft (93.7% vs 30.6%, P <.001). The prevalence of deep sternal wound infection was significantly lower in patients who received skeletonized grafts compared with patients who received conventional grafts (1.3% vs 11.1%, P =.03). Patients in the skeletonized group were also less likely to develop any (superficial or deep) sternal wound infection postoperatively (5.1% vs 22.2%, P =.03). There was no significant difference in the prevalence of deep sternal wound infection between patients with diabetes who received skeletonized internal thoracic arteries and patients without diabetes who underwent conventional internal thoracic artery grafting (n = 578) (1.2% vs 1.6%, respectively, P =.8). CONCLUSIONS: Skeletonization of internal thoracic artery conduits lowers the risk of deep sternal wound infection in patients with diabetes undergoing bilateral internal thoracic artery grafting. We no longer consider diabetes a contraindication to bilateral internal thoracic artery grafting, provided the internal thoracic arteries are skeletonized.

Adult↗
PubMed2003

Quadricuspid semilunar valves: report of two cases.

Quadricuspid semilunar valves are uncommon congenital anomalies sometimes associated with severe valvular dysfunction. Two cases of isolated quadricuspid semilunar valve were identified. The first, a heavily calcified quadricuspid aortic valve with four equal-sized cusps, was identified in a 56-year-old man at the time of valve replacement surgery for severe aortic stenosis and regurgitation. The second valve was a quadricuspid pulmonary valve with three equal-sized cusps and one smaller cusp, identified incidentally at autopsy in a 79-year-old woman with a ruptured abdominal aortic aneurysm. Review of the literature found that while quadricuspid pulmonary valves are infrequently associated with serious clinical complications, the majority of quadricuspid aortic valves are associated with clinically significant dysfunction, most commonly aortic insufficiency. Further, contrary to previous thinking, the frequency of aortic valvular dysfunction does not appear to be related to valve morphology.

Aged↗
PubMed2002

Aortic root replacement with anomalous origin of the coronary arteries.

Coronary arteries with anomalous origin from the aorta can be at risk during aortic valve procedures. We report a case of origin of the circumflex and left coronary artery from the proximal right coronary artery in a patient with a bicuspid aortic valve and aortic root aneurysm. Attention to the anatomic relationship of the anomalous arteries to the aorta allowed safe aortic root replacement.

Aged↗
PubMed2002

Aortic valve-sparing operations in patients with aneurysms of the aortic root or ascending aorta.

BACKGROUND: Aortic valve-sparing operations are an alternative to aortic root replacement in patients with aortic root aneurysms, or aortic valve replacement and supracoronary replacement of the ascending aorta in patients with ascending aorta aneurysms and dilated sinotubular junctions with consequent aortic insufficiency. METHODS: From 1988 to 2001, 230 patients underwent aortic valve-sparing operations for aortic root aneurysms (151 patients) or ascending aortic aneurysms with aortic insufficiency (79 patients). Two types of aortic valve-sparing operations were performed in patients with aortic root aneurysms: reimplantation of the aortic valve and remodeling of the aortic root. Mean follow-up was 3.8 +/- 2.8 years. RESULTS: Patients with aortic root aneurysms were younger, had less severe aortic insufficiency, less extensive vascular disease, and better left ventricular function than patients with ascending aorta aneurysms. The 8-year survival was 83% +/- 5% for the first group and 36% +/- 14% for the second. The freedom from aortic valve reoperation at 8 years was 99% +/- 1% for the first group and 97% +/- 2% for the second. In patients who had aortic root aneurysms, 3 developed severe aortic insufficiency (AI), and 15 developed moderate AI, for an 8-year freedom from significant AI of 67% +/- 7%. But freedom from AI was 90% +/- 3% after the technique of reimplantation, and 55% +/- 6% after the technique of remodeling (p = 0.02). In patients with ascending aortic aneurysms, the freedom from AI greater than 2+ at 8 years was 67% +/- 11%. CONCLUSIONS: The long-term results of aortic valve sparing for aortic root aneurysms are excellent, and reimplantation of the aortic valve may provide a more stable repair of the aortic valve than remodeling of the aortic root.

Adult↗
PubMed2002

Aortic valve replacement with the Toronto SPV: long-term clinical and hemodynamic results.

OBJECTIVE: Long-term durability and hemodynamics of stentless valves are unknown. Therefore, this study was undertaken to evaluate long-term clinical and echocardiographic outcome after aortic valve replacement with the Toronto stentless porcine valve (SPV) bioprosthesis at our institution. METHODS: Between 1991 and 1998, the Toronto SPV was implanted in 255 patients (mean age, 63+/-11 years, range 22-83 years, 181 males and 74 females). Preoperative diagnoses were aortic stenosis (76%), aortic insufficiency (12%) and mixed lesion (12%). New York Heart Association class III and IV were present in 49% (126/255) of the patients preoperatively. Mean valve size implanted was 26.5+/-2.1mm and in addition 34% (86/255) of the patients had coronary artery bypass surgery. RESULTS: Early mortality was 0.8% (2/255). Actuarial survival at 7 years was 90+/-3%. At 7 years, the freedom from cardiac death was 98+/-2%; from valve-related death, 99+/-1%; from valve reoperation, 97+/-2%; from structural valve degeneration, 97+/-2%; from thromboembolism, 95+/-2%; and from endocarditis, 99+/-1%. At 7 years of follow-up, the transvalvular peak and mean pressure differences across the aortic valve measured with Doppler echocardiography was 9.6+/-5.1 and 3.6+/-2.0 mmHg, respectively. CONCLUSIONS: The Toronto SPV has provided excellent clinical and hemodynamic results up until 7 years of follow-up.

Adult↗
PubMed2002

Intraoperative transesophageal echocardiography accurately predicts mitral valve anatomy and suitability for repair.

Mitral valve (MV) repair is the procedure of choice for MV prolapse or flail. However, valve repair is more technically demanding and requires a precise definition of MV morphology to determine the timing, complexity, and feasibility of repair. We prospectively examined 170 consecutive patients with MV prolapse or flail referred for MV repair. The MV valve was systematically assessed by intraoperative transesophageal echocardiography. MV anatomy was independently assessed at the time of operation. Accuracy of transesophageal echocardiography in identifying MV segments ranged from 90% to 97%, and was best for the middle segment/scallop of either anterior or posterior leaflet. MV repair was successful in 91% of patients. Success rate was the lowest (78%) in the presence of extensive bileaflet disease involving at least 2 segments of each leaflet. Independent predictors of unsuccessful repair were central jet of mitral regurgitation, calcification or severe dilatation of the mitral annulus, and extensive leaflet disease with involvement of at least 3 segments.

Adult↗
PubMed2002

Cerebral emboli during cardiopulmonary bypass: effect of perfusionist interventions and aortic cannulas.

Neuropsychological impairment is a very common complication of cardiopulmonary bypass (CPB). The principal cause of postoperative cognitive impairment is thought to be cerebral microemboli during CPB. We recently investigated the effects of perfusionist interventions and aortic cannulation techniques on cerebral emboli production during coronary bypass (CABG) surgery. Patients undergoing isolated CABG were monitored with continuous transcranial Doppler ultrasonography of the middle cerebral artery. Perfusionist interventions were defined as injections of drugs into the CPB circuit or acquisition of blood samples from the CPB circuit. Patients were randomized to receive either standard cannulation of the ascending aorta or cannulation of the distal aortic arch. Cerebral emboli were detected in all patients. The number of emboli per minute was markedly higher during perfusionist interventions than during other time periods. Patients with increased perfusionist interventions had worse neuropsychological outcomes. Cannulation of the distal aortic arch, with placement of the cannula tip beyond the cerebral vessels, resulted in significantly less cerebral emboli than cannulation of the ascending aorta. Perfusionist interventions are a common source of cerebral microemboli during CPB, and may contribute to postoperative neuropsychological impairment. Care should be taken to minimize the introduction of air into the bypass circuit during CPB. Provided it is performed safely, distal aortic arch cannulation is a useful technique for reducing cerebral emboli during cardiac surgery.

Aorta↗
PubMedDate not supplied

Explantation of a mechanical assist device: assessment of myocardial recovery.

Reliable predictors of myocardial recovery post-mechanical assist device implantation are not well defined. We report the case of a 29-year-old woman with refractory congestive heart failure due to acute myocarditis of unknown etiology. The patient was supported with a HeartMate (Thoratec Corp., Woburn, MI) left ventricular assist device for 100 days showing improvement in clinical status. Hemodynamic monitoring, dobutamine stress echocardiography, and cardiopulmonary testing were performed to identify myocardial recovery. Improvements in myocardial reserve, hemodynamic parameters, and myocardial oxygen consumption were identified prior to explantation. The patient was successfully explanted. This case confirms that myocardial recovery is feasible with the use of a mechanical assist device. This article describes our current left ventricular assist device weaning protocol.

Adult↗