PubMed Health⌕ Search

Biomedical subjects

Thoralf M Sundt

Publications and source records attributed to Thoralf M Sundt.

At least 37 records · Page 2Linked to original sources
PubMed2005

Severe symptomatic tricuspid valve regurgitation due to permanent pacemaker or implantable cardioverter-defibrillator leads.

OBJECTIVES: We report a series of patients with severe tricuspid valve regurgitation due to a permanent pacemaker (PPM) or implantable cardioverter-defibrillator (ICD) lead. BACKGROUND: Severe tricuspid regurgitation caused by a PPM or ICD lead is an under-recognized but treatable etiology of severe right heart failure. METHODS: We reviewed the records of 41 patients who underwent tricuspid valve operation for severe tricuspid regurgitation caused by previously placed PPM or ICD leads. RESULTS: During surgery, severe tricuspid regurgitation was found to be caused by the PPM or ICD leads in all 41 patients. There was a perforation of the tricuspid valve leaflet by the PPM or ICD lead in 7 patients, lead entanglement in the tricuspid valve occurred in 4 patients, lead impingement of the tricuspid valve leaflets occurred in 16 patients, and lead adherence to the tricuspid valve occurred in 14 patients. The septal leaflet was most often perforated (6 of 7). In the preoperative evaluation, valve malfunction due to the PPM or ICD lead was diagnosed preoperatively in only 5 of 41 (12%) patients by transthoracic echocardiography. All patients underwent successful tricuspid valve operation (22 tricuspid valve replacement), with one perioperative death occurring. During follow-up (range, 1 to 99 months), there was one patient who died from left-sided heart failure and three patients died of other causes. The remaining patients showed improvement in signs and symptoms of heart failure. CONCLUSIONS: Damage to the tricuspid valve by PPM or ICD leads may result in severe symptomatic tricuspid regurgitation and may not be overtly visualized by echocardiography. This etiology should be considered when evaluating patients with severe right heart failure after PPM or ICD implantation.

Aged↗
PubMed2005

Changing incidence, type, and natural history of conduction defects after coronary artery bypass grafting.

BACKGROUND: Cardiac conduction defects occur after cardiac surgery. We hypothesized that population aging and increased use of beta-blockers would increase the incidence of new conduction defects after coronary surgery. METHODS: We examined the medical records of 800 coronary artery bypass grafting (CABG) patients (400 from 1991 and 400 from 2001). Exclusion criteria included the following: preexisting conduction defect, permanent pacemaker, and perioperative atrial fibrillation, leaving 303 and 269 patients, respectively, included in the two study years. The incidence, type, and persistence of new conduction defects were determined from the preoperative, postoperative, and the predischarge electrocardiogram. Multivariate analysis identified predictors of new defects. RESULTS: Study populations were well-matched. There was a marked decrease in the incidence of new postoperative conduction defects from 1991 (19%) to 2001 (6%). There was also a change in the most frequently occurring block, from a right-bundle-branch-block in 1991 (10%) to first-degree atrioventricular block (3%) in 2001. Finally, conduction defects in 1991 were more transient. While 19% of 1991 patients showed a conduction defect early postoperatively, only 9% were persistent. In 2001, the incidence of conduction defects at discharge (7%), was equivalent to that early postoperatively (6%). Predictors of new conduction defects included year of operation, age, intraaortic balloon counterpulsation, number of vessels bypassed, and crystalloid cardioplegia. CONCLUSIONS: Our results were the opposite of those predicted. Our report identifies a changing incidence, type, and natural history of conduction defects after CABG. Our comparison demonstrated a decrease in the incidence of new conduction defects, as well as a qualitative change in the defects identified. Multivariate analysis provided predictors of new conduction defects after CABG.

Adult↗
PubMed2005

Surgical treatment of cardiac papillary fibroelastoma: a single center experience with eighty-eight patients.

BACKGROUND: Cardiac papillary fibroelastoma is a rare benign tumor that can cause thromboembolism. We have found no large surgical series describing its treatment and outcome. METHODS: A retrospective review of all patients treated surgically for this tumor from 1985 to 2002. RESULTS: There were 88 patients with a mean age of 62 +/- 16 years. Sixty-two (71%) were male. Cardiac papillary fibroelastoma was a primary indication for surgery in 47 (group 1, 53%) and an incidental finding in 41 (group 2, 47%). The common clinical symptoms were neurologic (group 1) and cardiac (group 2). Cardiac valves were predominantly involved (77%); the aortic valve was the most affected (52%). Other common sites were the left ventricular outflow tract (18%) and anterior mitral leaflet (11%). All heart valves were involved in one patient. Seventy-three patients (83%) had shave excision and 8 (9%) excision with valve repair. Of 5 (6%) valve replacements, 2 were for concurrent degenerative valve disease. Concomitant procedures included repair or replacement of another valve (32%), CABG (28%), and septal myectomy (19%). Surgical mortality occurred in 1 patient (2.1%) in group 1 who had concomitant lung resection for bronchiolitis obliterans. There was no tumor recurrence, and no tumor-related late morbidity or mortality at a mean follow-up of 3 years. CONCLUSIONS: Cardiac papillary fibroelastoma has a propensity to affect the anatomically contiguous structures of the aortic valve, left ventricular outflow tract, and anterior mitral leaflet. Surgical treatment by simple shave excision is low risk and can achieve good results.

Adult↗
PubMed2005

Irrigated radiofrequency ablation with transmurality feedback reliably produces Cox maze lesions in vivo.

BACKGROUND: Irrigated bipolar radiofrequency ablation has been used to replicate Cox maze surgical scars in pig hearts ex vivo. Impedance monitoring accurately predicted complete transmurality for all lesions. This study aimed to assess the feasibility and reliability of irrigated radiofrequency ablation and impedance monitoring to produce electrically isolating Cox maze lesions in vivo. METHODS: A modified Cox maze procedure was performed in 8 adult sheep during cardiopulmonary bypass using irrigated bipolar and unipolar radiofrequency ablation. For bipolar radiofrequency ablation, atrial tissues were clamped between opposing electrodes; ablation was terminated at the plateau in impedance decline. Unipolar radiofrequency ablation lesions were painted on the endocardium, and transmurality was assessed visually. Animals survived 30 days. RESULTS: Bipolar lesions (n = 48) were thinner (7.4 +/- 2.4 mm versus 12.7 +/- 3.2 mm) and required less time (14.1 +/- 3.4 seconds versus 41.4 +/- 21.8 seconds) and energy (377.5 +/- 99.2 W.s versus 995.1 +/- 547.1 W.s) to create despite being longer (31.7 +/- 8.6 mm versus 19.2 +/- 5.6 mm) than unipolar lesions (n = 26). The left atrial pacing threshold across selected bipolar lesions increased at least fivefold above baseline (1.6 +/- 0.2 mA) at 1 hour (18.4 +/- 4.6 mA; n = 8; p < 0.001) and 30 days (17.2 +/- 5.2 mA; n = 6; p < 0.001), indicating functional conduction block. Bipolar lesions had no adherent thrombus or endocardial defects. Cross-section examination confirmed transmurality in 100% of bipolar lesions and 98.7% of unipolar lesions. CONCLUSIONS: Irrigated bipolar radiofrequency ablation with impedance monitoring safely and reliably produces electrically isolating, transmural Cox maze lesions in vivo.

Animals↗
PubMed2005

Operative risk of reoperative aortic valve replacement.

OBJECTIVE: The contemporary risk of reoperative aortic valve replacement is ill-defined. We therefore compared the recent early results of reoperative and primary aortic valve replacement in our institution. METHODS: Between January 1993 and January 2001, a total of 162 patients underwent reoperative aortic valve replacement with or without coronary artery bypass grafting, and 2290 underwent primary aortic valve replacement with or without coronary artery bypass grafting. The reoperative and primary groups were similar with regard to gender (37% female in both), preoperative New York Heart Association functional class (2.8 +/- 1 vs 2.8 +/- 1), and ejection fraction (58% +/- 15% vs 57% +/- 15%). Patients undergoing reoperative aortic valve replacement were younger than those undergoing primary aortic valve replacement (64 +/- 15 years vs 70 +/- 13 years, P < .001). Previous prostheses were xenografts in 77 patients (48%), homografts and autografts in 25 (15%), and mechanical prostheses in 60 (37%). Mean time to reoperation was 9.7 +/- 6.8 years. RESULTS: Early mortality for reoperative aortic valve replacement (8/162, 5%) was not statistically different from that for primary aortic valve replacement (71/2290, 3%, P = .20). Endocarditis was more common in the reoperative group (22% vs 3%, P < .001); when endocarditis was excluded from the analysis, early mortality was 3% in both groups. Multivariate predictors for early mortality were prosthetic valve endocarditis ( P < .001, odds ratio 9.8), advanced preoperative functional class ( P < .001, odds ratio 2.0), peripheral vascular disease ( P = .008, odds ratio 2.0), preserved left ventricular ejection fraction ( P = .004, odds ratio 0.98), and male gender ( P = .009, odds ratio 0.49). After adjustment for these factors, there was no difference in early mortality between the groups ( P = .095). CONCLUSION: The risk of reoperative aortic valve replacement is similar to that for primary aortic valve replacement. These data support the expanded use of bioprosthetic valves in younger patients.

Age Factors↗
PubMed2005

Technology insight: randomized trials of off-pump versus on-pump coronary artery bypass surgery.

Coronary artery bypass grafting has proven a remarkably effective treatment for occlusive coronary artery disease, with demonstrable impact on both symptoms and survival. As conducted traditionally, cardiopulmonary bypass is required, and a global myocardial ischemic insult imposed with aortic occlusion under the protection of cardioplegic arrest. Despite the remarkable success of this approach, concerns over the systemic effects of bypass, including neurologic sequelae as well as ischemic myocardial injury, have stimulated development of techniques and technology to perform coronary bypass 'off-pump'. This technique obviates the need for the bypass machine and imposes only brief regional ischemia during construction of each individual anastomosis. Despite enthusiastic support by a devoted cohort of surgeons, and a host of nonrandomized retrospective studies demonstrating an apparent benefit to the off-pump technique, the technique has not been universally adopted. How can there be such controversy over what appears to be a superior approach? In part, many surgeons are concerned that the greater technical difficulty of the technique will impact long-term results adversely. There is also uncertainty with regard to the actual advantage of off-pump coronary artery bypass over the tried-and-true methods. Surgeons recognize that the results of any surgical series are particularly subject to the influence of subtle selection biases. Accordingly, prospective randomized studies add particular value to the debate. It is the aim of this review to examine the evidence for off-pump coronary artery bypass critically, from a surgeon's perspective, with particular emphasis on knowledge derived from a representative selection of published prospective randomized studies.

Cardiopulmonary Bypass↗
PubMed2005

Role of surgical revascularization in diabetic patients with coronary artery disease.

Diabetes is a well-known risk factor for morbidity and mortality associated with coronary artery disease. Currently, diabetics represent approximately a quarter of patients requiring coronary revascularization in the USA. The purpose of this article is to review and analyze the available data in surgical revascularization of diabetic patients with coronary artery disease. The review will also examine new developments in myocardial revascularization and assess their probable impact on the long-term outcome of diabetic patients.

Coronary Artery Disease↗
PubMed2004

Atrial fibrillation after surgical correction of mitral regurgitation in sinus rhythm: incidence, outcome, and determinants.

BACKGROUND: The incidence, determinants, and outcome of postoperative atrial fibrillation (AF) after surgery for mitral regurgitation (MR) are poorly defined but may have important implications for timing of mitral valve surgery. METHODS AND RESULTS: In 762 patients in sinus rhythm with no AF history undergoing MR surgical correction, we examined the rates and prognostic implications of postoperative AF for early AF (within 2 weeks postoperatively) and late AF (>2 weeks after surgery). During postoperative follow-up, 180 patients (24%) experienced new AF (early AF in 136 and late AF in 111). Isolated early AF without recurrence was observed in 69 patients characterized by high angina class and lower left ventricular ejection fraction but no significant left atrial (LA) enlargement. However, overall early AF predicted late AF: 62+/-5% of patients with early AF had late AF at 10 years compared with 9+/-1% of patients without early AF (P<0.0001). Large LA size strongly and independently predicted early AF (P=0.01) and late AF (P=0.003). For late AF, the predictive value of an enlarged LA was cumulative to that of early AF. Postoperative AF was associated with an increased subsequently higher risk of stroke or congestive heart failure (adjusted risk ratio=1.46 [1.04 to 2.05], P=0.03). CONCLUSIONS: Postoperative AF is common after surgical correction of MR in patients with no prior history of AF and is associated with increased subsequent morbidity. LA enlargement is independently predictive of postoperative AF and as such, should be integrated into the clinical decision-making process in patients with MR.

Aged↗
PubMed2004

Surgery for aneurysms of the aortic root: a 30-year experience.

BACKGROUND: This study evaluated long-term results of aortic root replacement and valve-preserving aortic root reconstruction for patients with aneurysms involving the aortic root. METHODS AND RESULTS: Two-hundred three patients aged 53+/-16 years (mean+/-SD; 153 male, 50 female) underwent elective or urgent aortic root surgery from 1971 to 2000 for an aortic root aneurysm: 149 patients underwent a composite valve conduit reconstruction, and 54 patients underwent valve-preserving aortic root reconstruction. Fifty patients had Marfan syndrome. In-hospital and 30-day mortality was 4.0% (8/203) overall: for a composite valve conduit procedure, the corresponding value was 4.0% (6/149) and for valve-preserving procedure, 3.7% (2/54) (P=NS). Morbidity included 3 strokes (1%), 10 perioperative myocardial infarctions (5%), and 8 reoperations for bleeding (4%). Actuarial survival at 5, 10, 15, and 20 years was 93% (95% confidence interval [CI] = 88% to 97%), 79% (95% CI = 71% to 87%), 67% (95% CI = 57% to 79%), and 52% (95% CI = 36% to 69%), respectively. Freedom from reoperation was 72% (95% CI = 54% to 86%) at 20 years. Complications with anticoagulation occurred in 29 patients; with valve thrombosis, in 2; and with hemorrhage, in 27 (4 life threatening and 23 minor). Freedom from thromboembolism was 91% (95% CI = 77% to 98%) at 20 years. Freedom from endocarditis was 99% (95% CI = 92% to 100%) at 20 years. Multivariate analysis revealed preoperative mitral valve regurgitation (+3 to 4) and older age to be significant predictors of late death (P< or =0.005), and Marfan syndrome, initial valve-preserving aortic root reconstruction, and need for a concomitant procedure at initial operation to be significant predictors of the need for reoperation (P< or =0.01). CONCLUSIONS: Aortic root replacement for aortic root aneurysms can be done with low morbidity and mortality. Composite valve conduit reconstruction resulted in a durable result. There were few serious complications related to the need for long-term anticoagulation or a prosthetic valve. Reoperation was most commonly required because of failure of the aortic valve when a valve-preserving aortic root reconstruction was performed or for other cardiac or aortic disease elsewhere.

Adult↗
PubMed2004

Risk of repeat mitral valve replacement for failed mitral valve prostheses.

BACKGROUND: Advances in tissue prosthetic valve design and manufacturing have stimulated renewed interest in the use of biological valves in younger patients. This approach, however, risks reoperation. We therefore reviewed our recent experience with repeat mitral valve replacement to better define its contemporary risks. METHODS: Using a computerized database, we identified and compared 106 patients undergoing repeat mitral valve replacement with 562 control patients undergoing primary mitral valve replacement between January 1993 and December 2000 at our institution. RESULTS: There were no significant differences between repeat and primary surgery groups with respect to age (mean 66 +/- 12 vs 64 +/- 13 years), gender distribution (women 65% vs 64%), preoperative functional class, ejection fraction, or active endocarditis (6.6% vs 3.4%). The indication for reoperation in the repeat group was structural dysfunction in 49 patients (46%), paravalvular leak in 21 patients (20%), nonstructural dysfunction in 11 patients (10%), and progression of other native valve disease in 8 patients (8%). Prior prostheses were mechanical in 46 patients (43%). Mean time to reoperation was 11.5 +/- 7.1 years. There were 5 deaths out of 106 patients in the repeat group (4.7%) and there were 23 deaths out of 562 patients in the control group (4.1%) (p = NS). Multivariate analysis identified prior myocardial infarction (p = 0.014, odds ratio 2.9) and nonelective surgical status (p = 0.004, odds ratio 2.3) as significant predictors of operative mortality. CONCLUSIONS: The risk of repeat mitral valve replacement was low suggesting that there should be less reluctance to recommend patients choose a bioprosthesis over a mechanical prosthesis. Given the expected durability of current designs, bioprosthetic use may be explored in younger patients without subjecting those individuals to excessive risk.

Aged↗
PubMed2004

Role of intraoperative transesophageal echocardiography in patients having coronary artery bypass graft surgery.

BACKGROUND: Previous studies have shown that intraoperative transesophageal echocardiography provides important preoperative and postoperative information in various cardiac and noncardiac surgeries that may alter patient management and outcome. The role of intraoperative transesophageal echocardiography in patients in whom isolated coronary artery bypass graft surgery is anticipated has been reported only in small selected groups. This study was designed to prospectively evaluate the role of intraoperative transesophageal echocardiography in a large, nonselected group of patients undergoing primarily coronary artery bypass graft surgery. METHODS: From January 2001 to December 2003, 474 consecutive patients (76% men, 24% women) aged 30 to 89 years (mean age of 70 +/- 10 years) who were undergoing coronary artery bypass graft surgery had prebypass and postbypass intraoperative transesophageal echocardiography. New findings and alterations in the surgical plan were documented prospectively. RESULTS: New prebypass findings were found in 10% of patients, and the surgical plan was altered in 3.4% of patients. New postbypass findings were found in 3.2% of patients, altering the surgical plan in 2% of patients. CONCLUSIONS: This large consecutive, nonselected, prospective study reveals the significant impact of intraoperative transesophageal echocardiography in patients having coronary artery bypass graft surgery as a primary procedure. New findings (prebypass and postbypass) were found in 13% of patients overall, and the surgical plan was altered in 5.5% of patients. This study supports the use of intraoperative transesophageal echocardiography in patients undergoing primarily coronary artery bypass graft surgery.

Adult↗
PubMed2004

Noninvasive, quantitative assessment of left ventricular function in ischemic cardiomyopathy.

BACKGROUND: Coronary artery disease characteristically impacts left ventricular (LV) function on a regional basis, although ultimately global function may be affected as well. Echocardiography is commonly clinically used for the assessment of regional function; however, it is only semiquantitative and in its current iteration is only two-dimensional in nature. Magnetic resonance imaging (MRI) with tissue tagging offers the possibility for noninvasive, three-dimensional (3D) assessment of transmural and segmental left ventricular strain and, thereby, function. Accordingly, we have explored methodologies to accurately and quantitatively characterize regional systolic function in three dimensions in patients with ischemic heart disease using MRI. MATERIALS AND METHODS: MRI radiofrequency tissue tagging was performed at rest and during dobutamine administration (10 mg/kg/min) on 10 normal volunteers (age: 26 +/- 6) and 8 patients with severe ischemic cardiomyopathy (age: 60 +/- 5, EF 26 +/- 11%). Three-dimensional global and regional systolic strain calculations were made based on 3D myocardial point displacements and compared with conventional measures. RESULTS: Global left ventricular strains were significantly decreased in ischemic patients at rest (0.14 +/- 0.04 versus 0.25 +/- 0.02, P < 0.001) and with dobutamine (0.14 +/- 0.03 versus 0.29 +/- 0.03, P < 0.001). In the regional analysis (216 LV wall segments) this methodology accurately differentiated normal from abnormally contracting regions. CONCLUSIONS: Noninvasive dobutamine MRI tissue tagging with calculation of 3D regional strains has significant promise as a clinical tool which is capable of the identification, quantification, and display of regionally varying ventricular function.

Aged↗
PubMed2004

Ventricular function after coronary artery bypass grafting: evaluation by magnetic resonance imaging and myocardial strain analysis.

OBJECTIVE: Magnetic resonance imaging with radiofrequency tissue tagging permits quantitative assessment of regional systolic myocardial strain. We sought to investigate the utility of this imaging modality to quantitatively determine preoperative impairment and postoperative improvement in ventricular function in patients with ischemic heart disease. METHODS: Magnetic resonance imaging with radiofrequency tissue tagging was performed on 6 patients (average age 60.2 +/- 13.7 years) with coronary artery disease and 32 control subjects with no known heart disease. Patients with coronary artery disease underwent imaging before and 3 months after coronary artery bypass grafting. The ventricle was divided into 6 segments within a midventricular plane. Regional 2-dimensional left ventricular circumferential strain was calculated from tagged magnetic resonance images throughout systole. Circumferential strain results were compared in patients before and after and 3 months after coronary artery bypass grafting and also in control subjects. RESULTS: Before the operation circumferential strain identified 100% (10/10) of all regional wall motion abnormalities seen by preoperative ventriculography. Postoperatively, improvements were demonstrated in 56% (20/36) of the regions, and these improvements agreed with viability testing by single-photon emission computed tomography when available. Additionally, preoperative global circumferential strain for the ischemic group was significantly depressed relative to that in control subjects (0.11 +/- 0.05 vs 0.20 +/- 0.03, P <.001). Global circumferential strain correlated with ejection fraction by ventriculography (r = 0.84, P <.01) and improved after coronary artery bypass grafting (0.14 +/- 0.05 vs 0.11 +/- 0.05, P <.01). CONCLUSIONS: Magnetic resonance imaging with radiofrequency tissue tagging permitted circumferential strain calculation. This technology quantitatively demonstrated improvements in left ventricular wall motion after coronary artery bypass grafting for both individual regions and the entire ventricle. This noninvasive method may prove useful in preoperative evaluation and postoperative serial assessment of left ventricular wall motion.

Adult↗
PubMed2004

Penetrating atherosclerotic ulcer of the descending thoracic aorta and arch.

OBJECTIVE: The clinical behavior of penetrating atherosclerotic ulcers of the aorta is controversial. We reviewed our experience with this entity over a 25-year interval. METHODS: Cases were identified using the Department of Radiology database searching for the diagnoses of aortic dissection, intramural hematoma, or penetrating ulcer between 1977 and 2002. Available imaging studies were reviewed by a vascular radiologist to confirm the diagnosis of penetrating ulcer and perform serial measurements. RESULTS: One hundred five patients with penetrating atherosclerotic ulcers of the descending thoracic aorta or arch with (n = 85) or without (n = 20) associated intramural hematoma were confirmed. Two patients with ulcers in the ascending aorta were excluded. There were 73 men and 32 women with a mean age of 72 +/- 9 years. Comorbidities included hypertension in 97 (92%), tobacco use in 81 (77%), and coronary artery disease in 48 (46%). Of nonoperated patients with follow-up studies, the mean thickness of the intramural hematoma decreased at 1 month in 89% and completely resolved at 1 year in 85%. There were 3 deaths (4%) within 30 days among 76 patients treated medically and 6 deaths (21%) among 29 patients treated surgically (P <.05). Failure of medical therapy defined as surgery or death was predicted by rupture at presentation (odds ratio = 20.6) and era of treatment (before 1990, odds ratio 9.9) but not aortic diameter, ulcer size, or extent of hematoma. CONCLUSION: Although careful follow-up is necessary, many penetrating atherosclerotic ulcers of the thoracic aorta can be managed nonoperatively in the acute setting.

Aged↗
PubMed2003

Trends in the surgical management of ischemic mitral regurgitation.

The surgical approach to ischemic mitral regurgitation (IMR) remains a topic of considerable controversy. Will coronary artery bypass alone suffice, or should the valve be intervened upon? The poor late survival of patients with IMR is well recognized, but it remains unknown if this can be altered by addressing the valve directly. And if surgery is undertaken, should the valve be repaired or replaced? The underlying mechanisms of IMR remain incompletely understood, and although current theory focuses on the role of alterations in ventricular geometry in its pathogenesis, IMR is most often addressed by annuloplasty alone. Is this sufficient, or does the ventricle itself require "remodeling?" The debate is confounded by imprecise terminology that fails to distinguish between acute and chronic disease, and active ischemia from completed infarction. Available clinical information is from retrospective studies with all of their inherent limitations and potential for bias. Still, progress is being made as increasing attention is focused on this clinically important entity.

Cardiac Surgical Procedures↗