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Biomedical subjects

Lawrence H Cohn

Publications and source records attributed to Lawrence H Cohn.

At least 55 records · Page 3Linked to original sources
PubMed2004

Left anterior descending coronary endarterectomy: early and late results in 196 consecutive patients.

BACKGROUND: With advances in percutaneous coronary interventions, many patients now referred for coronary artery bypass grafting have diffuse coronary artery disease. We undertook this retrospective study to determine whether left anterior descending (LAD) coronary endarterectomy is a safe and effective long-term adjunct to coronary artery bypass grafting in patients who cannot otherwise be completely revascularized. METHODS: Between January 1992 and March 2000, 196 of 7,633 (2.5%) consecutive patients underwent LAD coronary endarterectomy with coronary artery bypass grafting. Median age was 67 years (range, 33 to 97 years), 101 patients (52%) had unstable angina, and 182 (93%) were in New York Heart Association class III or IV. Thirty-three patients (17%) had ongoing myocardial infarction; another 17 (9%) had myocardial infarction less than 1 month. Thirty patients (15%) required intraaortic balloon pump preoperatively and 19 (10%) were reoperations. RESULTS: All patients underwent LAD endarterectomy with coronary artery bypass grafting to the LAD. The left internal mammary artery was grafted to the LAD in 151 patients (77%), and 46 of 151 (30%) of these required an additional vein patch to the endarterectomized bed. Concomitant valve procedures were performed in 8 (4%) patients. Overall hospital mortality was 3% (6 of 196). Perioperative myocardial infarction in the LAD territory was 3%. One-year survival was 94% (95% confidence interval, 90% to 97%), whereas 5-year survival was 74% (95% confidence interval, 66% to 80%). Freedom from cardiac events (angina, myocardial infarction, congestive heart failure, percutaneous coronary interventions) was 90% (95% confidence interval, 84% to 94%) at 1 year and 84% (95% confidence interval, 75% to 90%) at 5 years. CONCLUSIONS: Despite the presence of diffuse coronary artery disease, coronary artery bypass grafting with LAD endarterectomy offers excellent results with very low hospital mortality and morbidity, and favorable long-term survival.

Adult↗
PubMed2004

One thousand minimally invasive valve operations: early and late results.

OBJECTIVE: We sought to evaluate the potential benefits of minimally invasive approaches for treatment of isolated aortic and mitral valve disease. METHODS: From 7/96 to 04/03, we performed 1000 minimally invasive valve operations: 526 aortic (AV) procedures (64 years; mean, 25-95) and 474 mitral (MV) procedures (58 years; mean, 17-90). RESULTS: In the AV group, an upper ministernotomy was used in 492/526 patients (93%) and a right parasternal approach in 34 (7%). Sixty-three patients had reoperative aortic valve replacements. In the MV group lower sternotomy was used in 260/474 (55%), right parasternal in 200/474 (42%), and a right thoracotomy in 14 patients. MV repair was performed in 416 and MV replacement in 58 patients. Operative mortality was 12/526 (2%) in the AV and 1/474 (0.2%) in the MV group. Freedom from reoperation at 6 years was 99% and 95% in the AV and MV group, respectively. Late mortality was 5% in the AV and 3% in the MV group, respectively. CONCLUSIONS: Minimally invasive valve surgery can be performed at very low levels of morbidity and mortality, with results equal to or better than conventional techniques. All forms of valve repair and replacement operations can be performed. Long-term survival and freedom from reoperation are excellent.

Adult↗
PubMed2004

Aortic valve replacement in patients with severely reduced left ventricular function.

Aortic valve replacement (AVR) can be done safely in patients with severe aortic stenosis (AS) and depressed ventricular function (ejection fraction < or =35%). Dobutamine echocardiography is useful to identify AS patients with contractile reserve who will benefit from AVR and can be used for risk stratification of these patients. AVR can also be undertaken in patients with severe aortic regurgitation and depressed ventricular function with an acceptable operative mortality. AVR in both groups results in a 5-year survival of approximately 70%, which is similar to that of orthotopic heart transplantation. Due to the comorbidities of immunosuppression and limited donor organ supply, AVR should be attempted prior to transplantation in both these high-risk groups.

Aortic Valve↗
PubMed2004

Tailored surgical therapy for acute native mitral valve endocarditis.

BACKGROUND AND AIM OF THE STUDY: Mitral valve repair has been shown superior to valve replacement for the treatment of non-infectious valve disease. The criteria and results of valve repair for native valve endocarditis are still being defined. The study aim was to examine the short- and long-term results of mitral valve repair and replacement for acute infective endocarditis and to define criteria for the use of each technique. METHODS: A total of 53 consecutive patients who presented with acute native mitral valve infective endocarditis (diagnosed less than six weeks before surgery) between January 1992 and June 2002 was retrospectively analyzed. RESULTS: Twenty-one patients (40%) underwent mitral valve repair, and 32 (60%) underwent valve replacement. Operative mortality was 0% for the repair group and 13% (4/32) for the replacement group (p = 0.14). Median follow up was 4 years (range: 6-108 months). At five years follow up, a median ejection fraction (EF) of 60% and mitral regurgitation (MR) grade of 1/4 was observed, with an overall late survival of 85% (19/21), in the repair group, while the replacement group had a median EF of 55% and an overall late survival of 73% (p = 0.73). Recurrent endocarditis occurred in 2/21 (10%) in the repair group and 1/32 (3%) in the replacement group (p = 0.34). CONCLUSION: Mitral valve repair is a safe and effective technique to treat acute native mitral valve infective endocarditis with favorable short- and long-term morbidity and mortality. Patients with advanced endocarditis and annular destruction require valve replacement. Mitral valve repair should be performed when technically feasible.

Acute Disease↗
PubMed2004

Current results of combined coronary artery bypass grafting and mitral annuloplasty in patients with moderate ischemic mitral regurgitation.

BACKGROUND AND AIM OF THE STUDY: Combined coronary artery bypass grafting (CABG) and mitral annuloplasty for ischemic mitral regurgitation (MR) is historically associated with high operative mortality, and remains controversial in the setting of moderate ischemic MR. Herein, operative mortality rates in patients undergoing combined CABG and mitral annuloplasty for moderate ischemic MR were examined. METHODS: Between January 1992 and August 1999, 108 patients with moderate (grade 3+) ischemic MR and coronary artery disease underwent combined CABG and mitral annuloplasty. Univariable analysis was used to identify perioperative risk factors associated with operative mortality in patients undergoing surgery during two different time periods (1992-95 versus 1996-99). Bivariable logistic regression was used to evaluate the possible effect of era on operative mortality, while controlling for potential confounders. RESULTS: The overall operative mortality was 6.4%. During 1992-95 the operative mortality was 14% (4/28), but fell to 3.7% (3/80) during 1996-99 (p = 0.07). Patients from the earlier period were more likely to have unstable angina, worse NYHA functional class, and preoperative atrial fibrillation. Patients from the latter period were more likely to have peripheral vascular disease and chronic obstructive pulmonary disease. The unadjusted odds ratio (OR) for operative mortality associated with the earlier era was 4.3 (95% CI 9-20.8; p = 0.07). In the bivariable logistic regression models, where patient characteristics that potentially were responsible for the difference in mortality were added, the OR for operative mortality associated with the 1992-95 era ranged from 3.4 to 6.7. None of the patient characteristics appreciably reduced this risk. CONCLUSION: Recent decreased operative mortality in combined CABG and mitral annuloplasty for moderate ischemic MR suggests that a more liberal application of this approach may be warranted.

Aged↗
PubMed2003

Near-infrared fluorescent type II quantum dots for sentinel lymph node mapping.

The use of near-infrared or infrared photons is a promising approach for biomedical imaging in living tissue. This technology often requires exogenous contrast agents with combinations of hydrodynamic diameter, absorption, quantum yield and stability that are not possible with conventional organic fluorophores. Here we show that the fluorescence emission of type II quantum dots can be tuned into the near infrared while preserving absorption cross-section, and that a polydentate phosphine coating renders them soluble, disperse and stable in serum. We then demonstrate that these quantum dots allow a major cancer surgery, sentinel lymph node mapping, to be performed in large animals under complete image guidance. Injection of only 400 pmol of near-infrared quantum dots permits sentinel lymph nodes 1 cm deep to be imaged easily in real time using excitation fluence rates of only 5 mW/cm(2). Taken together, the chemical, optical and in vivo data presented in this study demonstrate the potential of near-infrared quantum dots for biomedical imaging.

Animals↗
PubMed2003

Robotic mammary takedown and off-pump bypass surgery for single-vessel disease of the left anterior descending coronary artery.

Robotic takedown of the left internal mammary artery and direct off-pump anastomosis to the left anterior descending artery through small thoracotomy incisions can be done safely with minimal morbidity and is associated with decreased blood loss, decreased ventilatory requirements, less intensive care unit stay, and less overall length of stay. It should be considered as an alternative to percutaneous angioplasty and stenting for those with isolated left anterior descending artery disease.

Adult↗
PubMed2003

Hypothermic circulatory arrest for the surgical treatment of complicated adult coarctation of the aorta.

OBJECTIVES: This study was designed to evaluate the surgical treatment of recurrent coarctation by a new technique. BACKGROUND: Recurrent coarctation either from aneurysm or recurrent constriction is a difficult problem in the adult because of the possible interruption of important collateral circulation. METHODS: We reviewed four patients who underwent recurrent coarctation surgery with the use of deep hypothermic circulatory arrest (HCA). RESULTS: All four patients survived. Deep HCA facilitated precise surgical resection and there was no postoperative paraplegia, stroke, or myocardial infarction. CONCLUSIONS: Deep HCA and resection and grafting of the coarctation is indicated for complicated adult coarctations, particularly when the collateral circulation is in doubt.

Adult↗
PubMed2003

Metastatic carcinoid tumor of the heart.

Although carcinoid heart disease has been well described in the literature, metastatic implantation in the heart is rare. We describe a 79-year-old man with no previous history of cancer who presented with progressive dyspnea. He was found to have a septal implantation of a previously undiagnosed metastatic carcinoid tumor. He underwent successful resection with an uneventful postoperative course.

Aged↗
PubMed2003

Minimally invasive mitral valve repair suggests earlier operations for mitral valve disease.

OBJECTIVE: We began minimally invasive mitral valve surgery in August, 1996, to reduce hospital costs, to improve patient recovery, cosmetic appearance, and to decrease trauma, yet maintain the same quality of surgery. To validate this approach we reviewed our entire experience through May 2002. METHODS: From August 1996 to May 2002, we performed 413 minimally invasive mitral valve operations including 51 mitral valve replacements and 362 mitral valve repairs. Excluding 4 robotically assisted repairs, we evaluated 358 patients, using the mitral valve repairs as the basis for this retrospective survey. These operations were performed through a 6- to 8-cm minimally invasive incision, beginning with parasternal and, most recently, lower ministernotomy (181 patients). The mitral valve reparative techniques include repair of 94 prolapsed anterior leaflets, posterior leaflet resection, leaflet advancement, commissuroplasty, Polytetrafluoroethylene (PTFE; Gore-Tex, W. L. Gore & Associates, Inc, Flagstaff, Ariz) chordal placement, and ring annuloplasty. Cannulation sites varied but primarily utilized a miniaturized system of 24F catheters in both the inferior and superior venae cavae with assisted venous suction. The Cosgrove ring was used in 95% of the patients undergoing this procedure. RESULTS: The operative mortality was 0/358. Perioperative morbidity included a 26% incidence of new atrial fibrillation, 2% incidence of pacemaker implantation, 0.5% incidence of deep sternal wound infection, and 1.9% incidence of stroke after an operation. There were 10 arterial and 3 venous complications. The mean length of stay was 6 days and 208 patients stayed < or =5 days. Only 25% of the patients underwent homologous blood transfusion. The mean follow-up was 36 months with 1.4% lost to follow-up. There were 12 late deaths and a survival at 5 years of 95%. There were 21 valves requiring reoperation for structural valve failure of 5.8%. The probability of freedom from reoperation at 5 years was 92%. CONCLUSION: This study documents the safety of minimally invasive mitral valve repair surgery in 358 patients. It also documents a low incidence of homologous blood use, requirement for post-hospital rehabilitation, and general morbidity.

Adolescent↗
PubMed2003

Hypercholesterolemia is a risk factor for bioprosthetic valve calcification and explantation.

OBJECTIVE: There are pathophysiologic similarities between calcification and atherosclerosis. We wished to determine whether risk factors for atherosclerosis were linked to bioprosthetic valve calcification and dysfunction. METHODS: We performed a retrospective cohort study on 144 patients at a single institution who had bioprosthetic aortic or mitral valves removed, serum cholesterol levels recorded, and valve calcification assessed on the basis of hematoxylin and eosin staining and radiography of the valve. We also performed case-control analysis of a group of 66 patients whose tissue valves were explanted and compared them with an age- and position-matched group of 66 patients with similar duration of implantation. We also compared mean serum cholesterol levels. RESULTS: In the retrospective cohort study cholesterol (P =.035), younger age at implantation (P =.014), and coronary artery disease (P =.017) were linked to calcification of the valve by means of univariate analysis. In stepwise multiple regression analysis only the mean serum cholesterol level was linked to calcification (P =.02). Sex, hypertension, smoking, diabetes, and implant position were not linked to calcification. In the case-control analysis the mean serum cholesterol level of the explanted valve group was significantly higher (189 vs 163 mg/dL, P <.0001) than that of the group whose valves did not require explantation. For those whose serum cholesterol levels were greater than 200 mg/dL, the odds ratio was 3.9 (95% confidence interval, 1.7-8.9) for valve explantation. CONCLUSIONS: Increased serum cholesterol level may be a risk factor for bioprosthetic valve calcification requiring explantation.

Adult↗