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David S Bach

Publications and source records attributed to David S Bach.

13 recordsLinked to original sources
PubMed2004

Atrial reduction plasty Cox maze procedure: extended indications for atrial fibrillation surgery.

BACKGROUND: The Cox maze procedure yields good results for atrial fibrillation (AF). However, patients with predictors of failure-chronic long-standing AF, low amplitude fibrillatory waves, and large left atriums-are generally thought not to benefit from a maze procedure. We report an aggressive approach for these patients, utilizing biatrial reduction plasty concomitantly with the Cox maze procedure for AF. METHODS: A complete Cox maze procedure utilizing supplemental RF ablation was performed in 36 patients. All underwent resection of both atrial appendages and biatrial reduction plasty encompassing resection of the left atrial posterior wall from left to right pulmonary veins and from inferior pulmonary veins to the mitral annulus, as well as removal of the right atrial lateral wall. Mitral or tricuspid valve repair, or both, was performed on 32 patients. RESULTS: These patients had a mean AF duration of 45 +/- 89 months. Their preoperative left atria measured 66 +/- 16 mm, with mean AF waves of 0.74 +/- 0.3 mm. Mean preoperative New York Heart Association class was 2.7 +/- 0.7 and left ventricular ejection fraction was 48 +/- 9. Cross clamp and bypass times were 91 +/- 35 minutes and 124 +/- 33 minutes, respectively. The average posterior left atrial tissue resected was 5.4 x 2.1 cm, and mean resected atrial weight was 10.3 +/- 2 g. There were no deaths and length of stay was 5.5 +/- 2 days. At a follow-up time of 19 +/- 16 months, 32 of the 36 patients were in normal sinus rhythm and New York Heart Association class I. CONCLUSIONS: Aggressive biatrial reduction plasty Cox maze procedure was effective in 89% of these "low success" AF patients. This simple procedure can extend utilization of the Cox maze procedure to more patients with chronic AF.

Aged↗
PubMed2004

Eight-year results after aortic valve replacement with the Freestyle stentless bioprosthesis.

OBJECTIVES: We sought to describe the hemodynamic and clinical outcomes for the Freestyle aortic root bioprosthesis (Medtronic, Inc, Minneapolis, Minn) in a large multicenter cohort prospectively followed for 8 years. METHODS: A total of 700 patients (651 [93%] >60 years of age) at 8 centers in North America were followed prospectively after aortic valve replacement with the Freestyle stentless bioprosthesis; the implant technique was subcoronary in 500, total root in 162, and root inclusion in 38. Follow-up was 3395 patient-years (4.9 +/- 2.3 years per patient). Clinical and echocardiographic follow-up was prospectively obtained at yearly intervals. RESULTS: For the subcoronary, total root, and root inclusion groups, actuarial freedom from valve-related death was 96.8% (SE 3.0%), 92.3% (SE 7.7%), and 90.9% (SE 11.2%), respectively, and freedom from structural deterioration was 98.6% (SE 2.0%), 100.0% (SE 0.0%), and 100.0% (SE 0.0%), respectively. Hemodynamics remained excellent at 6 years. Freedom from moderate or more aortic regurgitation was 86.0% (SE 5.1%), 98.7% (SE 3.9%), and 97.3% (SE 6.6%), respectively. Gradients were slightly lower (P =.0009), and the effective orifice area (P =.02) and freedom from aortic regurgitation were slightly higher (P =.03) with total root than subcoronary implantation. CONCLUSIONS: The Freestyle stentless aortic root bioprosthesis is a versatile option for aortic valve replacement. Measures of clinical outcomes and prosthesis durability remain excellent in multicenter follow-up through 8 years in a population predominantly older than 60 years at the time of the operation.

Adult↗
PubMed2004

Durability and prevalence of aortic regurgitation nine years after aortic valve replacement with the Toronto SPV stentless bioprosthesis.

BACKGROUND AND AIM OF THE STUDY: Stentless aortic bioprostheses have excellent hemodynamics. Previous investigations of the Toronto SPV valve described a correlation between the occurrence of significant aortic regurgitation (AR) and dilation of the sinotubular junction. The study aim was to determine the long-term durability and determinants of AR at nine years in a large, multicenter study of the Toronto SPV valve. METHODS: The study included 447 patients from six centers. Clinical outcomes and echocardiographic data (gradients, effective orifice area index (EOA-I), left ventricular mass, aortic root dimensions, and presence and severity of AR) were collected prospectively. A multivariable logistic regression model was used to evaluate clinical and echocardiographic variables for impact on the occurrence of AR. RESULTS: Total follow up was 2,660 patient-years (mean 6.0 +/- 2.5 years; range: 0 to 11.1 years). Mean gradient and EOA-I remained unchanged through nine years. There were 17 cases of structural deterioration, of which 15 underwent explantation. The mechanism of failure was predominantly leaflet tear in the setting of sinotubular dilation. Freedom from explant for structural failure was 90.1% at nine years (100% for patients aged > or = 65 years). Freedom from hemodynamically significant AR was 96.9% at five years and 82.5% at nine years. Determinants of AR were longer duration of follow up, larger valve size, and increase in the ratio of sinotubular junction to the size of valve implanted. CONCLUSION: At nine years after implantation of the Toronto SPV valve, hemodynamics remained excellent. There was good freedom from structural deterioration through nine years, and structural failure occurred due to aortic root dilation and leaflet tear, without significant valve calcification. AR tends to occur with longer follow up, larger valve sizes, and dilation of the sinotubular junction.

Adult↗
PubMed2004

Initial experience with the Toronto Root bioprosthesis.

BACKGROUND AND AIM OF THE STUDY: The study aim was to assess the safety and efficacy of the Toronto Root bioprosthesis for aortic root or valve replacement during the early postoperative stages. METHODS: Between November 2000 and December 2002, the Toronto Root was implanted in 191 patients in 17 institutions. The patients' mean age was 65 years (range: 25 to 87 years) and 70% were males. The bioprosthesis was implanted as a full aortic root in 76% of patients, as a root inclusion in 9%, and in the subcoronary position in 15%. The sizes used in decreasing frequency were 27, 29, 25, 23 and 21 mm. Coronary artery bypass was performed in 25% of patients. Echocardiography was performed before hospital discharge and at six months postoperatively. Serum aluminum levels were monitored pre- and postoperatively as this metal is used in anticalcification treatment of the arterial wall of the porcine root. For the purpose of this study, follow up was closed at six months in all patients, and was complete. RESULTS: Eight patients died, though none of the deaths was valve-related. Two patients required reoperation because of technical errors during implantation. Two patients developed endocarditis, one patient required surgical intervention, and two patients suffered cerebral transient ischemic attacks. All survivors experienced symptomatic improvement, and 97% were in NYHA functional classes I and II at six months postoperatively. Blood levels of aluminum were unchanged at follow up. The mean effective orifice area of all valves studied was 2.0 +/- 0.8 cm2, and the mean systolic gradient 7.0 +/- 3.9 mmHg at six months postoperatively. No patient had more than trace aortic insufficiency. CONCLUSION: Early experience with the Toronto Root bioprosthesis has shown it to be a safe and effective valve for aortic valve or aortic root replacement, with excellent hemodynamic characteristics, a low transvalvular gradient and a large effective orifice area.

Adult↗
PubMed2004

Intraoperative transesophageal echocardiography after aortic valve replacement does not predict subsequent transvalvular gradients.

BACKGROUND AND AIM OF THE STUDY: Intraoperative transesophageal echocardiography (TEE) can be used to assess gradients after aortic valve replacement (AVR). However, altered cardiac output after weaning from cardiopulmonary bypass, dynamic changes in valve function early after surgery, and limitations in transducer alignment may compromise the ability to predict valve hemodynamics on follow up. The study aim was to compare gradients on intraoperative TEE immediately after AVR with gradients on transthoracic echocardiography (TTE) after two to four months. METHODS: Among 90 patients who underwent AVR between September 2002 and April 2003, 31 had both intraoperative 'post-pump' TEE, including transaortic gradients, and TTE at two to four months after surgery. Mean and peak transvalvular gradients were compared between time periods, and a receiver operator curve (ROC) was constructed to test the ability to predict a mean gradient >15 mmHg (upper quartile of patients) on follow up. RESULTS: There was no discernable correlation between mean gradient on intraoperative imaging and at follow up (R2 = 0.09; p = 0.11); for peak gradient there was a statistically significant but extremely weak correlation between time points (R2 = 0.17; p = 0.02). A ROC revealed very poor prediction of high mean gradient on follow up based on mean gradient on intraoperative TEE (area under curve 0.63). CONCLUSION: Gradients on intraoperative TEE immediately after AVR do not correlate with later gradients on TTE. The mean gradient on intraoperative TEE holds no useful predictive value for a high mean gradient at follow up.

Aged↗
PubMed2003

Choice of prosthetic heart valves:update for the next generation.

Intervention for valvular heart disease poses unique clinical challenges in cardiology because the diseases are of relatively low prevalence, the interventions do not lend themselves to randomized comparative trials, and important clinical end points are assessed only after decades of follow-up. In addition, continuing advances in prosthetic heart valve technology make follow-up a moving target because long-term data by definition are available only for older prostheses. Newer tissue and mechanical prostheses afford superior hemodynamics compared with their older counterparts, and data suggest that durability and patient mortality are superior with newer compared with older bioprostheses. Arbitrary cutoffs dictating valve choice based predominantly on patient age may not give appropriate weight to individual patient perspectives. In educating and counseling patients regarding choices in heart valve prostheses, the clinician should help the patient weigh the relative merits for the individual patient of projected mortality, valve durability, and requirement for anticoagulation, with associated freedom from re-operation, hemorrhagic and thromboembolic risk, and impact on lifestyle.

Biomechanical Phenomena↗
PubMed2003

The sinotubular junction does not progressively dilate four years after modified subcoronary freestyle stentless tissue aortic valve replacement.

BACKGROUND AND AIM OF THE STUDY: Aortic root dilation at the sinotubular junction (STJ) results in aortic regurgitation associated with normal valves and with a complete subcoronary stentless aortic bioprosthesis. The study aim was to assess for progressive aortic root dilation following modified subcoronary Freestyle aortic valve replacement (AVR), and to compare for differences between implant techniques. METHODS: Aortic root diameter was measured at the annulus, sinuses of Valsalva, STJ and tubular aorta on post-pump transesophageal echocardiograms and on early (3-month) and late (>2 years) transthoracic echocardiograms among 16 patients after modified subcoronary Freestyle valve replacement, 16 after root inclusion, and three after total root replacement. RESULTS: Mean follow up was 3.9 +/- 0.8, 3.3 +/- 0.7 and 3.5 +/- 1.1 years for modified subcoronary, root inclusion and total root patients, respectively. The aortic annulus, sinuses and STJ increased in diameter to similar extents between surgery and three months after modified subcoronary and root inclusion surgery, with no further increase at late follow up (modified subcoronary STJ 18.4 +/- 3.7, 21.1 +/- 3.7 and 20.5 +/- 4.4 mm on intraoperative, early and late echocardiography, respectively; root inclusion STJ 21.8 +/- 3.9, 25.4 +/- 4.6 and 24.4 +/- 4.4 mm, respectively). There were no changes in aortic root diameter after total root replacement (STJ 23.7 +/- 1.2 and 25.7 +/- 6.0 on intraoperative and late follow up, respectively). Aortic regurgitation prevalence was low, and similar between groups. CONCLUSION: Small but significant increases in aortic root dimensions were seen during the first three months after modified subcoronary and root inclusion surgery, with no subsequent change. The early changes were likely caused by resorption of paravalvular edema and hematoma transiently affecting aortic root measurements in the perioperative period. There was no evidence of progressive STJ dilation at 3.9 years after modified subcoronary Freestyle AVR.

Aged↗
PubMed2002

Impact of implant technique following freestyle stentless aortic valve replacement.

BACKGROUND: Stentless aortic bioprostheses have excellent hemodynamics and clinical outcomes. The purpose of the present study was to determine whether implant technique of the Freestyle aortic root bioprosthesis impacts clinical outcomes or hemodynamic performance. METHODS: The long-term multicenter study of the Freestyle stentless aortic bioprosthesis includes 500 consecutive patients implanted using the subcoronary and 162 using the full root technique. Clinical outcomes and echocardiographic hemodynamics were compared through 5 years. RESULTS: There were no differences between groups in time to death, valve-related death, or reoperation. The incidence of operative death was higher in the full root than in the subcoronary group (odds ratio 3.97, p = 0.001). Patients in the subcoronary group were more likely to have New York Heart Association functional class III or IV symptoms at 1 year (1.7% versus 0%, p = 0.04) and 5 years postoperatively (4.4% versus 0%, p = 0.02). Mean gradient was lower (p = 0.0004) and effective orifice area larger (p = 0.04) in the full root group. Left ventricular mass index decreased in both groups. The preponderance of patients in both groups had no or trivial aortic regurgitation through 5 years. CONCLUSIONS: Full root implantation of the Freestyle stentless aortic bioprosthesis was associated with higher operative mortality, but somewhat better hemodynamics, functional class, and freedom from aortic regurgitation. Higher operative mortality argues against the empiric replacement of the ascending aorta in the absence of aortic root pathology. In appropriately selected patients, both implant techniques are viable alternatives for valve implantation.

Aged↗
PubMed2002

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

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

Adult↗
PubMed2002

Prognostic significance of mitral regurgitation and tricuspid regurgitation in patients with left ventricular systolic dysfunction.

BACKGROUND: Mitral regurgitation (MR) and tricuspid regurgitation (TR) frequently develop in patients with left ventricular systolic dysfunction (LVSD). Ventricular volume overload that occurs in patients with MR and TR may lead to progression of myocardial dysfunction. We hypothesized that MR and TR would provide markers of risk in patients with LVSD. METHODS: We reviewed clinical, electrocardiographic, and echocardiographic data on 1421 consecutive patients with LVSD (left ventricular ejection fraction < or =35%). Predictors of survival (freedom from death or United Network for Organ Sharing [UNOS]-1 transplantation) were identified in a multivariable analysis with a Cox proportional hazards analysis. The impact of MR and TR (none to mild, moderate, or severe) then was assessed separately with Kaplan-Meier survival analysis. RESULTS: During the follow-up period (mean +/- SD, 365 +/-364 days), death occurred in 435 study subjects (31%) and UNOS-1 transplantation in 28 subjects (2%). Multivariable predictors of poor outcome included increasing MR and TR grade, cancer, coronary artery disease, and absence of an implantable cardiac defibrillator. Relative risk was 1.84 (95% CI 1.43-2.38) for severe MR and 1.55 (95% CI 1.14-2.11) for severe TR. Survival with Kaplan-Meier analysis related inversely to MR grade (none to mild 1004 +/-31 days, moderate 795 +/-34 days, severe 628 +/-47 days, P <.0001) and TR grade (none to mild 977 +/-28 days, moderate 737 +/-40 days, severe 658 +/-55 days, P =.0001). CONCLUSION: Patients with severe MR or TR represent high-risk subsets of patients with LVSD. Future study is warranted to determine whether pharmaceutical or surgical strategies to relieve MR and TR have a favorable impact on survival.

Cardiomyopathy, Dilated↗
PubMed2002

Intraoperative transesophageal echocardiographic assessment of the effect of protamine on paraprosthetic aortic insufficiency immediately after stentless tissue aortic valve replacement.

Mild paravalvular aortic insufficiency (AI) is common immediately after stentless bioprosthetic aortic valve replacement. Although resolution of paraprosthetic jets with protamine has been described, the predictability of resolution has not been addressed. Intraoperative transesophageal echocardiography was performed before and after protamine administration among 2 groups. The first group (n = 20) was used to define the prevalence and severity of paravalvular AI after stentless tissue AVR, and define a threshold value for jet size associated with resolution with protamine. A second group (n = 18) was used to prospectively test the determined threshold. Paravalvular AI occurred in 13 of 20 (65%) patients. Using a threshold value of 0.3 cm or less jet width, prospective testing revealed positive and negative predictive values for AI resolution with protamine of 93% (14 of 15) and 100% (3 of 3), respectively. Protamine administration is associated with resolution of small AI jets immediately after implantation of a stentless aortic bioprosthesis, with a jet width 0.3 cm or less strongly predictive of resolution.

Adult↗
PubMed2002

Impact of small valve size on hemodynamics and left ventricular mass regression with the Toronto SPV stentless aortic bioprosthesis.

BACKGROUND AND AIM OF THE STUDY: The hemodynamic performance of stentless aortic bioprostheses has been previously well described. Because the potential for prosthesis-patient mismatch is greatest for small valves in the aortic position, the present study sought to compare the hemodynamic performance and degree of left ventricular (LV) mass regression between valve sizes for the Toronto SPV valve, with special interest in measures of relief of LV outflow obstruction afforded by the smallest valves. METHODS: This study included 257 patients (178 men, 79 women; mean age 63.5+/-11.4 years; range: 34-93 years) from six investigative centers with complete echocardiography/Doppler data obtained through three years. Valve sizes implanted were 21 mm (n = 11), 23 mm (n = 23), 25 mm (n = 58), 27 mm (n = 83), and 29 mm (n = 82). Echocardiography was performed at discharge, six months, one year, and yearly thereafter, and interpreted in a centralized core laboratory. Mean gradient, effective orifice area (EOA), indexed EOA, and absolute and percent change in LV mass index were used as markers of hemodynamic performance. RESULTS: For all valve sizes, mean and peak gradients fell and EOA increased early after surgery. There were no differences between groups in the degree to which gradients fell, and EOA increased from discharge to one year follow up. At one year, indexed EOA was 0.9 cm2/m2 for valve sizes 21 and 23 mm, and 1.0-1.2 cm2/m2 for sizes 25, 27 and 29 mm. There was statistically significant LV mass regression for all valve sizes (p <0.05), and no differences between valve sizes in the magnitude of absolute or percent change in LV mass index between baseline and three years. CONCLUSION: The Toronto SPV valve demonstrates excellent parameters of hemodynamic performance for all valve sizes, including the smallest valves used in only a minority of patients. Findings of indexed EOA > or = 0.9 cm2/m2, and equivalent degrees of LV mass regression for all valve sizes, reinforces the excellent hemodynamic performance of stentless aortic bioprostheses, and suggests that prosthesis-patient mismatch should be minimized with these valves.

Adult↗