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Biomedical subjects

Delos M Cosgrove

Publications and source records attributed to Delos M Cosgrove.

At least 19 recordsLinked to original sources
PubMed2006

Surgery for paroxysmal atrial fibrillation in the setting of mitral valve disease: a role for pulmonary vein isolation?

BACKGROUND: It is unknown whether pulmonary vein isolation or a complete Cox-Maze procedure is needed to ablate paroxysmal atrial fibrillation in patients with mitral valve disease. Our objective was to assess the impact of different surgical treatments for this arrhythmia in patients undergoing mitral valve surgery. METHODS: From July 1993 to January 2004, 152 patients underwent combined surgical treatment of paroxysmal atrial fibrillation and mitral valve disease. Ablation procedures included pulmonary vein isolation alone (n = 31, 20%), pulmonary vein isolation with left atrial connecting lesions (n = 80, 53%), and Cox-Maze (n = 41, 27%). The latter had longer durations of atrial fibrillation than the former (p < 0.0001). Rhythm documented on 1,225 postoperative electrocardiograms was used to estimate prevalence of, and risk factors for, atrial fibrillation across time. Ablation failure was defined as occurrence of atrial fibrillation any time beyond 6 months after operation. RESULTS: Prevalence of postoperative atrial fibrillation peaked at 22% at 2 weeks and declined to 9% at 1 year. Risk factors included older age (p = 0.09), larger left atrium (p = 0.05), and rheumatic (p = 0.003) and degenerative etiologies (p = 0.03). Freedom from ablation failure was 84% at one year. Ablation procedure did not affect prevalence of atrial fibrillation or incidence of ablation failure. CONCLUSIONS: Pulmonary vein isolation alone may be adequate treatment for patients with paroxysmal atrial fibrillation undergoing mitral valve surgery, particularly when it is of short duration. A randomized trial is necessary to examine this strategy, especially in patients with longer duration of paroxysmal atrial fibrillation.

Aged↗
PubMed2006

Are allografts the biologic valve of choice for aortic valve replacement in nonelderly patients? Comparison of explantation for structural valve deterioration of allograft and pericardial prostheses.

OBJECTIVE: To compare explantation for structural valve deterioration in nonelderly patients after aortic valve replacement with stented bovine pericardial and cryopreserved allograft valves. METHODS: From 1981 to 1985, 478 patients received pericardial prostheses during premarket approval; from 1987 to 2000, 744 patients received cryopreserved allografts. Mean age of patients receiving allografts was 49 +/- 12 years, and that of those receiving pericardial prostheses was 65 +/- 11 years; pericardial valves were used in 138 patients younger than age 60. Mean follow-up was 15 +/- 5.1 years for pericardial valves (4674 patient-years of follow-up) and 5.6 +/- 3.1 years for allografts (3892 patient years of follow-up). Multivariable hazard function methodology, age-group stratification, and propensity matching were used to compare age-specific explantation for structural valve deterioration. RESULTS: Ninety-five pericardial valves and 46 allografts were explanted, and structural valve deterioration was the mechanism of failure in 74% and 59%, respectively. The risk of structural valve deterioration increased with younger age at implantation for both allografts (P = .07) and pericardial valves (P < .0001), with a similar magnitude of effect in patients age 50 years or younger (P = .5), 50 to 60 years (P = .7), and greater than 60 years (P = .9) and in propensity-matched pairs (P = .2). Thus, pericardial valves were as durable as allografts at all adult ages. CONCLUSIONS: Structural valve deterioration is the most frequent cause of valve-related reoperation after both pericardial and allograft aortic valve replacement and is similarly age dependent, suggesting that pericardial valves may be appropriate for nonelderly as well as older persons.

Adult↗
PubMed2006

Magnesium as a neuroprotectant in cardiac surgery: a randomized clinical trial.

OBJECTIVE: We sought to evaluate magnesium as a neuroprotectant in patients undergoing cardiac surgery with cardiopulmonary bypass. METHODS: From February 2002 to September 2003, 350 patients undergoing elective coronary artery bypass grafting, valve surgery, or both were enrolled in a randomized, blinded, placebo-controlled trial to receive either magnesium sulfate to increase plasma levels 1(1/2) to 2 times normal during cardiopulmonary bypass (n = 174) or no intervention (n = 176). Neurologic function, neuropsychologic function, and depression were assessed preoperatively, at 24 and 96 hours after extubation (neurologic) and at 3 months (neuropsychologic, depression). Neurologic scores were analyzed using ordinal longitudinal methods, and neuropsychologic and depression inventory data were summarized by principal component analysis, followed by linear regression analysis using component scores as response variables. RESULTS: Seven (2%) patients had a postoperative stroke, 2 (1%) in the magnesium and 5 (3%) in the placebo group (P = .4). Neurologic score was worse postoperatively in both groups (P < .0001); however, magnesium group patients performed better than placebo group patients (P = .0001), who had prolonged declines in short-term memory and reemergence of primitive reflexes. Three-month neuropsychologic performance and depression inventory score were generally better than preoperatively, with few differences between groups (P > .6); however, older age (P = .0006), previous stroke (P = .003), and lower education level (P = .0007) were associated with worse performance. CONCLUSIONS: Magnesium administration is safe and improves short-term postoperative neurologic function after cardiac surgery, particularly in preserving short-term memory and cortical control over brainstem functions. However, by 3 months, other factors and not administration of magnesium influence neuropsychologic and depression inventory performance.

Aged↗
PubMed2006

Morbidity and mortality risk associated with red blood cell and blood-component transfusion in isolated coronary artery bypass grafting.

OBJECTIVE: Our objective was to quantify incremental risk associated with transfusion of packed red blood cells and other blood components on morbidity after coronary artery bypass grafting. DESIGN: The study design was an observational cohort study. SETTING: This investigation took place at a large tertiary care referral center. PATIENTS: A total of 11,963 patients who underwent isolated coronary artery bypass from January 1, 1995, through July 1, 2002. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Among the 11,963 patients who underwent isolated coronary artery bypass grafting, 5,814 (48.6%) were transfused. Risk-adjusted probability of developing in-hospital mortality and morbidity as a function of red blood cell and blood-component transfusion was modeled using logistic regression. Transfusion of red blood cells was associated with a risk-adjusted increased risk for every postoperative morbid event: mortality (odds ratio [OR], 1.77; 95% confidence interval [CI], 1.67-1.87; p<.0001), renal failure (OR, 2.06; 95% CI, 1.87-2.27; p<.0001), prolonged ventilatory support (OR, 1.79; 95% CI, 1.72-1.86; p<.0001), serious infection (OR, 1.76; 95% CI, 1.68-1.84; p<.0001), cardiac complications (OR, 1.55; 95% CI, 1.47-1.63; p<.0001), and neurologic events (OR, 1.37; 95% CI, 1.30-1.44; p<.0001). CONCLUSIONS: Perioperative red blood cell transfusion is the single factor most reliably associated with increased risk of postoperative morbid events after isolated coronary artery bypass grafting. Each unit of red cells transfused is associated with incrementally increased risk for adverse outcome.

Aged↗
PubMed2005

The Cox maze procedure in mitral valve disease: predictors of recurrent atrial fibrillation.

OBJECTIVES: The Cox maze procedure is the gold standard for ablation of atrial fibrillation in patients undergoing mitral valve surgery, and new approaches to atrial fibrillation ablation must be compared with it. Therefore, we sought to determine the time-related prevalence of atrial fibrillation and its risk factors after combined Cox maze and mitral valve surgery. METHODS: From November 1991 through January 2004, 263 patients (mean left atrial diameter, 5.8 +/- 1.2 cm) underwent combined mitral valve surgery (repair in 71%) and a cut-and-sew Cox maze procedure for atrial fibrillation (permanent, 74%; persistent, 7%; paroxysmal, 16%). Rhythm documented on 2367 postoperative electrocardiograms was used to estimate the prevalence of atrial fibrillation across time. RESULTS: Hospital mortality was 1.9%. Postoperative atrial fibrillation prevalence peaked at 36% at 2 weeks, decreasing to 21% at 5 years. Risk factors for higher postoperative atrial fibrillation prevalence varied with time and included longer duration of preoperative atrial fibrillation (P = .003), larger left atrial diameter (P = .01), older age (P = .0002), and higher left ventricular mass index (P = .02). CONCLUSIONS: In some patients undergoing mitral valve surgery and a Cox maze procedure, atrial fibrillation recurs over time, mandating close, long-term follow-up of heart rhythm. Earlier operation and left atrial size reduction should be considered to improve results in selected patients.

Atrial Fibrillation↗
PubMed2005

Commissural closure for repair of mitral commissural prolapse.

With traditional mitral valve repair techniques, prolapse at a commissure presents a surgical challenge. When commissural prolapse is identified, simple closure of the commissure combined with annuloplasty enables rapid and reliable mitral valve repair.

Chordae Tendineae↗
PubMed2005

Importance of moderate ischemic mitral regurgitation.

BACKGROUND: The importance of moderate ischemic mitral regurgitation in patients presenting for coronary artery bypass grafting (CABG) is controversial. Therefore, we tracked the course of unrepaired moderate ischemic mitral regurgitation after CABG surgery alone, identified factors associated with worsening postoperative ischemic mitral regurgitation, and assessed the impact of unrepaired moderate ischemic mitral regurgitation on survival. METHODS: From 1980 to 2000, 467 patients with moderate ischemic mitral regurgitation underwent CABG alone. The course of unrepaired mitral regurgitation was estimated by a longitudinal analysis of 267 follow-up echocardiograms from 156 patients. The survival impact of moderate ischemic mitral regurgitation was determined among propensity-matched patients with and without ischemic mitral regurgitation. RESULTS: Mitral regurgitation was dynamic early postoperatively. Immediately postoperatively, it was absent or mild in 73% and severe in 6%; by 6 weeks, these figures were 40% and 22%, respectively. The course of postoperative mitral regurgitation was not associated with the preoperative extent of coronary artery disease or left ventricular dysfunction. Five-year survival of matched bypass patients without ischemic mitral regurgitation was 85% compared with 73% for patients with moderate ischemic mitral regurgitation (p = 0.003). CONCLUSIONS: Moderate ischemic mitral regurgitation does not reliably resolve with CABG surgery alone and is associated with reduced survival. Therefore, a mitral valve procedure may be warranted for such patients presenting for CABG. A randomized trial comparing strategies of revascularization with mitral valve repair and revascularization alone is required to determine optimal treatment.

Adult↗
PubMed2005

Comparison of saphenous vein and internal thoracic artery graft patency by coronary system.

BACKGROUND: We sought to compare saphenous vein and internal thoracic artery graft patency by coronary system. METHODS: From 1972 to 1999, 50,278 patients underwent primary coronary surgery; subsequently, 4,333 had angiography of 2,121 internal thoracic artery and 8,733 saphenous vein grafts. Longitudinal analysis was used to model graft occlusion and identify risk factors. Using the model, patency was calculated twice for each graft and compared first as if an internal thoracic artery, and second as if a saphenous vein, were used. RESULTS: Unadjusted 1-, 5-, and 10-year patency was 93%, 88%, and 90% for internal thoracic arteries and 78%, 65%, and 57% for saphenous veins. At 10 years, internal thoracic arteries were more likely than saphenous veins to be patent to left anterior descending in 99.1% of cases, to diagonals in 98.3%, to circumflex in 98.3%, to posterior descending artery in 98.5%, and to right coronary arteries in 82.5%. For right coronary arteries, saphenous vein patency was equivalent to or better than internal thoracic artery patency early after surgery. However, by 10 years, internal thoracic artery patency was better in right coronary arteries with 70% stenosis or greater. At all times after surgery and all levels of clinically important coronary stenosis, internal thoracic artery patency surpassed saphenous vein patency in grafts to the left anterior descending, diagonal, circumflex, and posterior descending arteries. CONCLUSIONS: Internal thoracic arteries demonstrate better patency than saphenous veins except when grafting moderately stenosed right coronary arteries. When bypassing right coronary arteries with less than 70% stenosis, saphenous veins may be a better choice.

Coronary Angiography↗
PubMed2005

Feasibility of valve repair for regurgitant bicuspid aortic valves--an echocardiographic study.

BACKGROUND: There is increasing interest in the role of valve repair for patients with isolated severe aortic regurgitation. Those with bicuspid aortic valves are suggested as most suitable for repair. Morphologic features of these valves that suggest feasibility of repair are not well defined. METHODS: Perioperative echocardiograms on 132 consecutive patients (mean age 42 +/- 12 years; 94% male), with bicuspid valves and isolated aortic regurgitation undergoing surgery at our institution were reviewed. Seventy-five patients (57%) underwent successful valve repair. Repair was attempted but unsuccessful for another 8 patients (6 intraoperatively and 2 before discharge). RESULTS: Cusp prolapse was the most common primary mechanism of regurgitation (88 patients [67%]), with 81 patients having primarily eccentrically directed regurgitation. Echocardiographic examination of 72 (55%) had evidence of cusp thickening with 40 (30%) having cusp calcification. By multivariate analysis, an eccentric regurgitant jet direction (odds ratio = 14.3; 95% confidence interval [CI] = 3.4 to 59.6), lack of cusp thickening (odds ratio = 5.9 [1.7 to 20]), lack of cusp calcification (odds ratio = 4.2; [1.1 to 16.7]) and the absence of commissural thickening (odds ratio = 4.8 [1.3 to 16.7]) were independently associated with a greater likelihood of successful valve repair. Greater cusp thickening was the only factor associated with attempted but failed repair. CONCLUSIONS: Successful repair of regurgitant bicuspid aortic valves was more feasible for those patients with eccentric regurgitant jets, those without cusp or commissural thickening or cusp calcification. Recognition of these features may enhance patient selection and improve procedural outcomes with aortic valve repair.

Adult↗
PubMed2005

Minimally invasive left ventricular epicardial lead placement: surgical techniques for heart failure resynchronization therapy.

BACKGROUND: Epicardial lead placement for biventricular pacing is often a rescue procedure after failed coronary sinus cannulation. This study aims to determine perioperative and early postoperative outcome of minimally invasive left ventricular lead placement as a management strategy for heart failure, comparing minithoracotomy and endoscopic approaches. METHODS: From October 2002 through October 2003, 41 patients underwent minimally invasive left ventricular lead placement, 23 (56%) by minithoracotomy and 18 (44%) endoscopically. Thirty-one (76%) were males, 19 (46%) had previous cardiac surgery, 21 (51%) had ischemic cardiomyopathy, 17 (41%) were in New York Heart Association class III or IV, and 28 (65%) had implantable cardioverter-defibrillators. RESULTS: There were no in-hospital deaths, intraoperative complications, or failures to implant the left ventricular lead. Median operative time was longer for the endoscopic approach (188 minutes) than for minithoracotomy (151 minutes; p = 0.006). Preoperatively, the endoscopic group had more mitral regurgitation (median, 2.5 versus 1.0, respectively; p = 0.009). QRS duration was shorter postoperatively (mean change from preoperative, -32 +/- 24 ms; p < 0.0001); this change was unrelated to surgical approach. Impedance also was less postoperatively (mean change, -490 +/- 300 ohms; p < 0.0001), and the change was unrelated to surgical approach. Changes were greater the larger their preoperative values (p < 0.0001). Threshold increased with follow-up time (adjusted p < 0.0001), but impedance decreased (adjusted p = 0.0009); these trends were similar for both approaches. No changes were evident in left ventricular dimensions. CONCLUSIONS: Minimally invasive left ventricular epicardial lead placement is safe and effective, offering selection of the best pacing site with minimal morbidity; it can be considered a primary option for resynchronization therapy.

Aged↗
PubMed2005

Ischemic versus degenerative mitral regurgitation: does etiology affect survival?

BACKGROUND: Ischemic mitral regurgitation (MR) is associated with poor survival and degenerative MR with excellent survival. We hypothesized that in some patients with degenerative MR requiring concomitant coronary artery bypass grafting (CABG), ischemic disease would dominate prognosis, resulting in survival as poor as in patients with ischemic MR. Thus, we (1) determined survival impact of etiology (degenerative vs ischemic) after combined mitral valve repair and CABG and (2) explored survival differences within etiology groups. METHODS: From 1985 to 2003, 710 patients underwent mitral valve repair for degenerative MR and concomitant CABG (two diseases); 400 patients had mitral annuloplasty and CABG for functional ischemic MR (one disease). Patients were propensity-matched on demography, symptoms, comorbidities, coronary artery disease, and left ventricular function. Survival was compared between matched groups and within groups. RESULTS: Compared with patients with degenerative MR, those with ischemic MR had more extensive coronary artery disease, worse ventricular function, more comorbidities, and more symptoms (p < 0.05). Unadjusted 5-year survivals were 64% and 82% for patients with ischemic and degenerative MR, respectively. However, 123 ischemic and degenerative MR matched pairs had equivalently poor 5-year survival (p > 0.9), 66% and 65%, respectively. Among patients with degenerative MR, survival varied widely, depending largely on ischemic burden and extent of left ventricular dysfunction. CONCLUSIONS: The large survival discrepancy between patients with ischemic and degenerative MR is attributable to differences in patient profile, particularly extent of ischemic disease and left ventricular dysfunction. Thus, ischemic and degenerative MR patients with equivalent characteristics have equivalently poor survival.

Aged↗
PubMed2005

Surgical revision after percutaneous mitral valve repair with a clip: initial multicenter experience.

PURPOSE: Almost 50,000 mitral valve operations are performed annually in the United States, with an increasing number of repairs. Recently, a percutaneous mitral valve repair option that achieves edge-to-edge approximation with a clip has been described in patients with mitral regurgitation. DESCRIPTION: We describe 6 patients from three centers with mitral regurgitation after percutaneous repair who underwent reintervention. During open surgical revision, the clips were uneventfully removed in all patients with no limitation in surgical options. Five patients underwent repair and 1 underwent replacement. EVALUATION: After surgical revision, mitral regurgitation was significantly decreased, and all but 1 patient underwent uneventful recovery. One patient developed ilio-femoral deep venous thrombosis that was treated successfully with anticoagulation. CONCLUSIONS: Preserving standard of care options is critical with any evolving technology in the event of initial treatment failure. Standard surgical options were preserved in all of the patients who underwent percutaneous mitral valve edge-to-edge repair. Furthermore, a thorough understanding of the clip design, in particular its unlocking mechanism, is essential and facilitates surgical clip removal.

Adult↗
PubMed2005

Surgical ablation of atrial fibrillation with bipolar radiofrequency as the primary modality.

OBJECTIVES: In studying cardiac surgical patients undergoing atrial fibrillation ablation with bipolar radiofrequency, we sought to (1) quantify the time-related prevalence of atrial fibrillation postoperatively and identify its risk factors and (2) determine time-related ablation failure and its risk factors. METHODS: From November 2001 to January 2004, 513 patients underwent atrial fibrillation ablation (bipolar radiofrequency alone or with cryothermy) and other cardiac operations. Rhythm documented on 3495 postoperative electrocardiograms was used to estimate the prevalence of and risk factors for atrial fibrillation across time. Ablation failure was defined as occurrence of atrial fibrillation any time beyond 6 months after operation. RESULTS: Prevalence of postoperative atrial fibrillation peaked at about 1 month, decreased to 13% at 6 months, and gradually increased thereafter. Risk factors associated with increased prevalence varied by time period and included older age ( P = .004) for early occurrence, lesion set in permanent atrial fibrillation ( P = .02) for late occurrence, and larger left atrial diameter ( P = .02) and permanent atrial fibrillation ( P < .0001) for occurrence across the entire time span. Freedom from ablation failure was 72% at 12 months. Risk factors for ablation failure included lesion set in permanent atrial fibrillation ( P = .001), longer duration of atrial fibrillation ( P = .01), and larger left atrial diameter ( P = .03). CONCLUSIONS: Bipolar radiofrequency enables extension of ablation to most cardiac surgical patients with atrial fibrillation. Recurrence is influenced by the type and duration of atrial fibrillation, choice of lesion set in permanent atrial fibrillation, and left atrial size. Early operation, careful choice of lesion set, and left atrial reduction might enhance results.

Aged↗
PubMed2005

A novel device for left atrial appendage exclusion.

OBJECTIVE: The left atrial appendage is a frequent source of thromboemboli in patients with atrial fibrillation. Exclusion or excision of the left atrial appendage may reduce the risk of stroke in patients with atrial fibrillation. We evaluated the ability of a novel device to exclude the left atrial appendage during early and intermediate follow-up periods in a canine model. METHODS: Eight mongrel dogs (mean weight 29.1 +/- 4.0 kg) were used in this study. The occlusion device, constructed from 2 stainless steel strips covered with a knit braided polyester fabric, was implanted at the base of the left atrial appendage through a left thoracotomy on a beating heart. Dogs were evaluated at 7 days (n = 2), 30 days (n = 2), and 90 days (n = 4) by epicardial echocardiography, left atrial angiography, histologic inspection, and gross pathology. RESULTS: Device implantation was performed without complications in all animals. Complete exclusion of the left atrial appendage from the circulation was confirmed acutely and chronically by echocardiographic and angiographic evaluations. There was no device migration or damage to adjacent structures. CONCLUSION: This novel device enables rapid, reliable, and safe exclusion of the left atrial appendage. The device provides a new therapeutic option for reducing the risk of stroke in patients with atrial fibrillation.

Animals↗
PubMed2005

Tricuspid valve repair for biopsy-induced regurgitation in a heart transplant recipient.

Tricuspid regurgitation (TR) is a frequent complication after heart transplantation. The etiology of TR is multifactorial, but biopsy-induced flail leaflet is one of the most important mechanisms. A 61-year-old woman underwent heart transplant, but experienced several rejection episodes which required multiple surveillance endomyocardial biopsies. At three months after transplant, she required tricuspid valve repair due to symptomatic severe TR. The anterior leaflet was flail, with rupture of primary and secondary chordae. Valve repair was performed with a triple leaflet edge-to-edge technique. The procedure consisted of suture fixation of the prolapsed anterior leaflet joining to the septal and posterior leaflets, and placement of a 30-mm annuloplasty ring. The patient was uneventfully discharged home on day 7 with trivial TR. At a four-years post-transplant evaluation, she was in NYHA functional class I, with preserved ventricular function and trivial TR. She has been followed closely because of post-transplant coronary artery disease.

Biopsy↗
PubMed2004

Bipolar radiofrequency to ablate atrial fibrillation in patients undergoing mitral valve surgery.

BACKGROUND: Atrial fibrillation (AF) affects 30% to 50% of patients undergoing mitral valve surgery. The optimum treatment of AF in these patients is unclear. The purpose of this study was to describe initial clinical experience using a bipolar radiofrequency clamp to facilitate AF ablation in patients undergoing mitral valve surgery. METHODS: From November 2001 through March 2003 a bipolar radiofrequency clamp was used to facilitate AF ablation in 108 patients undergoing mitral valve surgery. Preoperative AF was paroxysmal in 25%, persistent in 26%, and permanent in 49% of the patients. All patients underwent bilateral pulmonary vein isolation performed with the bipolar radiofrequency clamp and excision or exclusion of the left atrial appendage. Most patients had connecting lesions between the right and left pulmonary veins and between the left atrial appendage and the left pulmonary veins. Novel statistical methods were used to create a plot of the prevalence of AF versus time after surgery. RESULTS: Mean time required for AF ablation was 17+/-4 minutes (range, 9-28 minutes). All patients left the operating room with sinus rhythm or with atrial or atrioventricular pacing for an underlying nodal rhythm. Perioperative AF was common, affecting 64% of patients. At discharge, 33% of patients were in AF or atrial flutter. By 3 months postoperatively, the predicted prevalence of AF or atrial flutter was 15%. There were no device-related complications. CONCLUSIONS: Bipolar radiofrequency facilitates rapid and safe AF ablation in patients with mitral valve disease. Perioperative AF is common and should be treated aggressively. By 3 months postoperatively, 85% of patients are free of AF or atrial flutter. Continued follow-up is necessary to document late results of this strategy.

Absorptiometry, Photon↗