Quantcast CTSNet Online Abstract Administration
57. Epicardial Atrial Defibrillation: Novel Treatment Of Postoperative Atrial Fibrillation
Amit N Patel; *Barron L Hamman; *Robert F Hebeler; *Richard E Wood
Baylor University Medical Center , Dallas , TX

Background:

Atrial fibrillation (AF) is the most common complication after cardiac surgery. Current medical treatment using antiarrhythmics and anticoagulants has a significant morbidity. The goal of this study was to determine if epicardial atrial defibrillation can be safely performed and return patients to sinus rhythm.

Methods:

A prospective analysis of patients undergoing cardiac surgery was performed. Patients with a prior pacemaker/defibrillator, history of arrhythmia, preoperative antiarrhythmic, and/or IABP were excluded. Temporary epicardial atrial cardioversion wires were placed on the right and left atrium. Bipolar atrial and ventricular pacing wires were also placed. The wires were tested in the operating room. Patients who went into postoperative AF were cardioverted with 3, 6, and/or 9J.

Results:

There were 45 patients enrolled. Sixteen patients (35%) went into postoperative AF during their hospital stay. Mean time to onset of AF was 2.6±1.4 days after surgery. Fifteen patients were successfully cardioverted to sinus rhythm on the primary cardioversion, with mean of 5.7±2.4J. One patient was cardioverted at 6hrs after onset of AF, at 6J. Recurrent AF occurred in 4 patients during their hospital stay. All 4 of these patients were cardioverted with a mean of 6.4±2.6J. All wires were removed the day before patients were discharged. There were no complications with wire insertion or removal. There were no adverse neurological events. The mean hospital stay was 5.1± 2.2 days. All patients were in sinus rhythm at early follow-up.

Conclusions:

The use of a temporary atrial defibrillator to resynchronize patients in postoperative AF is safe and effective.

58. Edge-to-edge Mitral Repair: A Versatile Mitral Repair Technique
Sunil K. Bhudia; *Patrick M. McCarthy; *Nicholas G. Smedira; Buu-Khanh Lam; Jeevanantham Rajeswaran; *Delos M. Cosgrove; Eugene H. Blackstone
The Cleveland Clinic Foundation , Cleveland , Ohio

Background:

Mitral repair can be challenging and edge-to-edge (Alfieri) mitral repair augments the repertoire of techniques to correct mitral regurgitation (MR). Objectives of this study were to determine operative risk, degree of mitral stenosis, and return of MR after edge-to-edge repair.

Methods:

From 01/97 to 10/01, 224 patients underwent edge-to-edge mitral repair (excluding patients with partial left ventriculectomy). The most common indications were ischemic cardiomyopathy (143/63%), myxomatous disease (31/14%), dilated cardiomyopathy (27/12%), and hypertrophic obstructive cardiomyopathy (14/6%). Concomitant mitral valve ring annuloplasty was performed in 188 patients (84%). Preoperative MR was 4+ in 109 patients (50%) and 3+ in 65 (30%). Postoperative and follow-up MR and mean mitral and peak mitral gradients were assessed using 402 transthoracic echocardiograms and ordinal longitudinal analysis.

Results:

Hospital mortality was 2% (5/224). Mitral valve mean gradient was low and nonprogressive (Table, P=.7), although peak gradient rose slightly (P=.01). Absence of MR declined to 40% during the first 3 postoperative months, and prevalence of 3+ MR increased to 14% and then slowly increased thereafter (Table). Fourteen patients, 12 within 2 years, required additional mitral valve surgery, none for mitral stenosis. Seven patients, 6 within 2 years, required heart transplantation.

Conclusions:

Edge-to-edge mitral repair can be used in a variety of settings with low operative mortality and a low risk of creating mitral stenosis. In this diverse group with complex MR, steadily increasing prevalence of recurrent MR is the first 3 months after edge-to-edge repair requires further study.

Measurement 7 days 3 months 6 months 1 year 2 years
Mean gradient (mmHg) 3.7 3.7 3.7 3.7 3.7
Peak gradient (mmHg) 8.4 8.6 8.8 9.2 10
3+ MR (% of patients) 7 14 17 21 24
4+ MR (% of patients) 1 2 3 4 4

59. Annular Geometric Remodeling In Chronic Ischemic Mitral Regurgitation
Frederick A. Tibayan1; Filiberto Rodriguez1; David Liang1; Mary K. Zasio1; Lynn Bailey1; George T. Daughters2; Neil B. Ingels2; *D. Craig Miller1; Frank Langer1
1Stanford University , Stanford , CA , 2Palo Alto Medical Foundation , Palo Alto , CA

Background:

Ring annuloplasty, the preferred treatment for chronic ischemic MR (CIMR), can be associated with recurrent/residual MR. More precise understanding of annular 3-D geometric remodeling in CIMR is requisite to improving surgical outcomes.

Methods:

Ten sheep underwent placement of 8 radiopaque markers around the mitral annulus. After 7 days, the animals were studied with biplane fluoroscopy and TEE (Baseline). Snare occlusion of the second and third obtuse marginal coronary arteries induced infarction of the inferior wall. After 7 weeks, fluoroscopic studies were repeated (CIMR). Mitral annular area (MAA), septal-lateral (S-L) and commissure-commissure (C-C) mitral diameters, and fibrous (inter-trigonal) and muscular annular perimeters were determined at their systolic minima and diastolic maxima. Maximum systolic and minimum diastolic heights of the “saddle horn” (mid-septal annulus) above the plane of the muscular annulus were determined.

Results:

MR increased from 0.6±0.5 to 2.8±0.8§. C-C dilation (18% increase from minimum, 19% from maximum) was proportional to S-L dilation (16% & 22%, respectively). Fibrous annulus lengthening (14% & 15%) was nearly equivalent to that of the muscular annulus (18% & 22%).
* = p < 0.0001 vs. Baseline Min or Max; § = p < 0.05 vs. Baseline Min or Max

Conclusions:

CIMR was associated with proportional dilation in the S-L and C-C dimensions. Surprisingly, lengthening of the fibrous annulus contributed significantly to overall annular enlargement. These findings argue for the use of a complete ring in CIMR to prevent further anterior annular (inter-trigonal) dilation. Rings that restore the saddle shape of the annulus may relieve leaflet stresses resulting from annular flattening induced by CIMR.

Baseline CIMR
Min Max Min Max
MAA (cm²) 7.66±0.91 8.46±0.89 10.72±2.22* 12.52±1.69*
S-L (cm) 2.78±0.23 2.99±0.20 3.23±0.45* 3.64±0.35*
C-C (cm) 3.47±0.35 3.71±0.32 4.05±0.38* 4.40±0.30*
Fibrous perimeter (cm) 3.16±0.36 3.36±0.37 3.61±0.44* 3.85±0.39*
Muscular perimeter (cm) 7.33±0.43 7.77±0.39 8.69±0.93* 9.51±0.72*
Saddle horn height (cm) 0.73±0.52 1.06±0.52 0.57±0.42§ 0.94±0.43§

60. The Bicuspid Aortic Valve. how Does It Function? why Does It Fail?
*Francis Robicsek1; Mano J. Thubrikar2; Michel Labrosse2; Chun-An Lin2; Brett Fowler2
1Carolinas Medical Center , Charlotte , North Carolina , 2Heineman Medical Research , Charlotte , North Carolina

Background:

Congenitally bicuspid aortic valve [CBAV] is the most common valvular malformation. While most valves function clinically and hemodynamically well during the early years, a significant number develop severe changes as time passes. To understand the cause of this, the function and the stresses acting upon the CBAV were investigated in vitro.

Methods:

Human cryopreserved CBAV’s mounted in a pulse duplicator were studied. The studies included 500 frames/sec. cinematography, hemodynamic measurements, intravascular ultrasound, and digital recreation of flow patterns.

Results:

The studies, which for the first time visually documented the function of the bicuspid human aortic valve, revealed that:

a) CBAV, even if it functions within normal hemodynamics, morphologically is always stenotic.
b) The abnormally “broad” leaflet approximation transfers the level of closure from the leaflet edge to the leaflet belly causing function-related deformation.
c) Due to abnormal flow, we calculated multifold increase of stresses upon the leaflets, which probably lead to deformation and calcification.
d) The stenosis generated turbulence exerts additional shear and mechanical stresses promoting aortic dilatation and dissection.
Conclusions:

Morphological and functional characteristics of CBAV place a high stress-load upon both the leaflets and the aortic wall even if hemodynamically not stenotic. This leads to calcification and predilects for dilatation and dissection of the aortic wall.

61. Influence Of Older Donor Grafts On Heart Transplant Survival: Lack Of Recipient Effects
Dipin Gupta; Valentino Piacentino III; Mahender Macha; Arun K Singhal; James B McClurken; John P Gaughan; Dan Beltramo; Satoshi Furukawa
Temple University School of Medicine , Philadelphia , PA

Background:

Marginal donors, particularly those >50 years, represent a potential resource of additional grafts for heart transplantation. Others have suggested that these hearts be targeted to older recipients. Our goal was to identify factors which may influence survival when using older donor hearts.

Methods:

Between June 1990 and June 2000, we performed 53 transplants using donor hearts 50 yrs. or older (GROUP A, mean donor age±SD, 53.8±3.0 yrs). This cohort was compared to 521 patients who received donor hearts <50 yrs. (GROUP B, 26.9±12.1 yrs). Multiple factors were analyzed using logistic regression, Chi-square analysis, and Cox proportional hazard regression.

Results:

GROUP A had reduced survival at 6 months (67.9% vs. 84.6%), 1 year (66.0% vs. 80.5%), and 5 years (46.5% vs. 68.4%, Kaplan-Meier, p<.01). The incremental risk for older hearts was consistent for all donor ages. Recipient gender, gender mismatch, pulmonary vascular pressures, recipient cardiac index, and ischemic time were similar in GROUPS A and B. GROUP A consisted of more recipients with ischemic cardiomyopathy (75% vs. 42.6%, p=.04), and more donors with the following characteristics: female (49% vs. 32.8%, p=.01), non-African American (96.2 % vs. 83.5%, p=.01), and race mismatch (79.2% vs. 64.2%, p=.02). None of these parameters were found to have a significant impact on survival. There was no significant relationship between donor age and recipient age (r²=.03).

Conclusions:

Our experience represents the largest single institution heart transplantation experience to date using grafts 50 years or older. The lack of differences between GROUPS A and B suggests that the reduced survival is inherent to the use of older grafts, rather than to recipient factors. These grafts should not be targeted to older patients, but rather to those with a higher acuity of illness.

62. Early Clinical Experience With An Implantable, Intracardiac Circulatory Support Device: Operative Considerations And Physiologic Implications
*O.H. Frazier1; Stephen Westaby2; Timothy J. Myers1
1Texas Heart Institute , Houston , Texas , 2Oxford Heart Centre , Oxford , United Kingdom

Background:

We have been investigating continuous-flow circulatory support devices for 20 years because they have several advantages over pulsatile devices: a simple power source and no need for compliance chambers or valves. Clinical experience with the Hemopump proved that an intravascular, high-speed axial flow pump could safely augment the circulation. Ten years of animal experiments with the larger, longer-term Jarvik 2000 confirmed the safety of an intraventricular pump.

Methods:

We studied the Jarvik 2000 in 23 operative survivors (20, bridge-to-transplant; 3, destination therapy).

Results:

Of the bridge-to-transplant patients, 11 underwent transplant, 7 died during support; 2 studies are ongoing. Support averaged 62 days. Follow-up for the surviving patients (all are in Class I) averaged 14.9 months. The average cardiac index (CI) increased 70.6% at 48 hrs (1.7 to 2.9 L/min/m2), and pulmonary capillary wedge pressure (PCWP) decreased 39.3% (22.9 to 13.9 mmHg). Similar results were seen for the destination-therapy patients. In that series, 1 patient died of subdural hematoma. The survivors are in Class I: 500 and 744 days after implant. Their average CI increased 89.5% (1.9 to 3.6 L/min/m2); PCWP decreased 52.2% (23 to 11 mmHg).

Conclusions:

Our early clinical experience has shown that the Jarvik 2000 can effectively offer long-term support for Class III and IV chronic heart failure patients. However, because of unanticipated complications resulting from the unique physiology of this pump in humans, we now believe the Jarvik 2000 should be implanted in patients with enough native cardiac function to allow some aortic outflow.