Prospective assessment of the CryoMaze procedure with continuous outpatient telemetry in 136 patients.

BACKGROUND: Only 40% of patients with atrial fibrillation (AF) undergoing cardiac surgery are treated with surgical AF correction. We prospectively studied endocardial cryoablation of the Cox-maze III lesion set following prespecified rhythm assessment with outpatient telemetry. METHODS: Between 2007 and 2011, 136 patients underwent surgical AF correction using an argon-powered cryoablation device. Patients wore continuous electrocardiogram monitoring prior to and at 6, 12, and 24 months after surgery. The average length of monitoring was 6.5±1 days prior to surgery and 11±4 days at each time point after surgery. Patients were assessed for cardiac rhythm, interval cardioversion or ablation procedures, pacemaker placement, and the use of warfarin or antiarrhythmic medications. The primary endpoint of this study was freedom from AF at 1 year. RESULTS: Mean patient age was 66±12 years, 50% (69 of 138) were male and 41% (55 of 134) had persistent AF. CryoMaze was done in conjunction with mitral valve operation in 95% (131 of 138) and other procedures in 41% (56 of 138). Follow-up was 96% complete at 1 year and 90% at 2 years. Freedom from AF was 76% at 1 year. Perioperative mortality and stroke rates were both 1.5% (2 of 138). Perioperative pacemaker implantation was required in 7% (9 of 136). In univariate analysis, younger age, female gender, decreased height and weight, smaller preoperative and postoperative left atrial diameter, intermittent AF, and freedom from AF at discharge were associated with freedom from AF at 1 year. Actuarial 2- and 4-year (Kaplan-Meier) survival were 93% and 80%, respectively. CONCLUSIONS: The CryoMaze procedure is safe and is associated with 76% freedom from AF at 1 year.

Pulmonary hypertension adversely affects short- and long-term survival after mitral valve operation for mitral regurgitation: implications for timing of surgery.

OBJECTIVE: We investigated the impact of preoperative pulmonary hypertension (PH) on early and late outcomes after mitral valve operation for mitral regurgitation. METHODS: Systolic pulmonary artery pressure (sPAP) was measured before operation in 873 consecutive patients who underwent mitral valve surgery for mitral regurgitation between January 2002 and January 2010. PH was classified as none (sPAP < 40 mm Hg), mild (40 ≤ sPAP < 50 mm Hg), moderate (50 ≤ sPAP < 60 mm Hg), or severe (sPAP ≥ 60 mm Hg). RESULTS: Increased preoperative sPAP was associated with greater left ventricular dysfunction and dilation, left atrial enlargement, more atrial fibrillation, and tricuspid regurgitation. Operative mortality was correlated with the degree of preoperative PH (2%, 3%, 8%, and 12% for none, mild, moderate, and severe PH, respectively, P < .0001). Long-term survival was related to preoperative sPAP (5-year survival: 88%, 79%, 65%, and 53% for none, mild, moderate, and severe PH, respectively; P < .0001). In multivariable analyses, sPAP was a predictor of both operative mortality (odds ratio, 1.023 per 1 mm Hg increase; 95% confidence interval, 1.003-1.044; P = .0270) and late death (hazard ratio, 1.018 per 1 mm Hg increase; 95% confidence interval, 1.007-1.028; P = .001). Among 284 patients with isolated degenerative mitral regurgitation due to leaflet prolapse, actuarial survival was 97.5%, 91.2%, and 80.5% for none, mild, and moderate to severe PH, respectively (P = .0002). CONCLUSIONS: Preoperative sPAP is a powerful predictor of early and late survival after mitral valve operation for mitral regurgitation. Even modest increases in sPAP adversely affect outcomes. Mitral valve operation should be performed before the development of PH.

Undersized tricuspid annuloplasty rings optimally treat functional tricuspid regurgitation.

BACKGROUND: In contrast to mitral valve repair, residual and recurrent regurgitation after tricuspid valve (TV) repair for functional tricuspid regurgitation (TR) is common. We have systematically used undersized, rigid 3-dimensional annuloplasty rings to treat functional TR. METHODS: From March 2006 to October 2009, 101 consecutive patients with moderate or greater functional TR underwent TV repair with an undersized rigid 3-dimensional annuloplasty ring. All patients had a predischarge echocardiography evaluation in a core echocardiography laboratory. Follow-up echocardiography was available for 96% of surviving patients. Mean follow-up was 17±9 months. RESULTS: Twenty-nine percent of patients had undergone previous cardiac operations, 74% were in New York Heart Association functional class III or IV, and 48% had atrial fibrillation. Mitral valve operations were performed in 93 patients, aortic valve operations in 17, coronary artery bypass grafting in 21, and CryoMaze procedures in 40. Size 26 or 28 rigid tricuspid annuloplasty rings were used in 88% of patients, and no ring larger than a 28 has been used since November 2008. The operative mortality rate was 6% (n=6). Freedom from significant TR (TR>moderate) at hospital discharge, as assessed by the clinical core laboratory, was 97%. Only 3% of patients had TR greater than moderate during follow-up. No patient required TV reoperation. New postoperative permanent pacemakers were inserted in 3 patients. CONCLUSIONS: Tricuspid valve repair with an undersized (size 26 or 28) rigid 3-dimensional annuloplasty ring is the method of choice for reliable and durable treatment of functional TR.

Early and midterm hemodynamics after aortic valve bypass (apicoaortic conduit) surgery.

BACKGROUND: Aortic valve bypass (AVB [apicoaortic conduit]) relieves aortic stenosis (AS) by connecting the apex of the left ventricle to the descending thoracic aorta with a valved conduit. AVB is performed through a small left thoracotomy, without cardiopulmonary bypass, aortic cross-clamping, cardiac arrest, or debridement of the native aortic valve. Little is known about hemodynamics, including ventricular performance, relative conduit blood flow, and progression of native AS after AVB. METHODS: Forty-seven very high risk patients underwent AVB for AS between 2003 and 2009. The mean age was 82 years. Predismissal and interval transthoracic quantitative two-dimensional and Doppler echocardiography was performed in a core laboratory. RESULTS: No patient had obstruction of the native aortic valve or the conduit during follow-up. The AVB effectively relieved left ventricular outflow tract obstruction (average peak gradient across the conduit was 5.6 +/- 3.8 mm Hg). Native aortic valve stenosis did not progress after AVB (0.63 +/- 0.16 cm(2) before surgery to 0.7 +/- 0.24 cm(2) at latest follow-up more than 6 months; p = 0.16). Total stroke volume increased after AVB from 60 mL +/- 22 mL to 107 mL +/- 27 mL (p < 0.0001). Left ventricular outflow was distributed in a predictable fashion between the conduit and the native aortic valve, with 63% +/- 10% of the flow directed to the conduit. Relative conduit flow remained stable (68% +/- 8%) at latest follow-up more than 6 months (p = 0.17). CONCLUSIONS: Aortic valve bypass effectively relieves the outflow tract obstruction of AS. Placement of an apical valved conduit halts the biologic progression of AS.

Intermediate-term outcomes of surgical atrial fibrillation correction with the CryoMaze procedure.

BACKGROUND: Few studies have reported long-term outcomes of surgical atrial fibrillation (AF) correction. We perform the Cox-Maze III lesion set with argon-powered cryoenergy (CryoMaze procedure) on all patients with AF presenting for cardiac operations. This study reports long-term clinical results and heart rhythm status. METHODS: Between July 2002 and November 2005, 119 consecutive patients underwent surgical AF correction with the CryoMaze procedure. Mitral valve disease was the primary indication for operation in 66%. AF was continuous in 65%. Rhythm assessment was with 2-week continuous electrocardiographic (ECG) monitoring in 75% of patients and by noncontinuous ECG in the remainder. Median follow-up was 3.2 years and was 98% complete. RESULTS: There was one hospital (0.8%) death. Survival at 3 years was 84%. One perioperative stroke resolved completely. No late strokes occurred. In 4 of 119 patients (4 (3.4%), pacemakers were inserted during the index hospitalization. Median length of stay was 7 days. Overall freedom from AF more than 3 years after operation was 60%. Among patients with preoperative intermittent AF, 85% (28 of 33) were in normal sinus rhythm, and 47% (27 of 58) with continuous AF were in normal sinus rhythm (p < 0.001). CONCLUSIONS: CryoMaze AF correction is safe and is associated with a very low risk of stroke. Rates of normal sinus rhythm at more than 3 years postoperatively were high for patients with intermittent AF and acceptable for those with continuous AF. This experience supports wider application of the CryoMaze to all patients with AF who need cardiac operations.

Aortic valve bypass surgery: midterm clinical outcomes in a high-risk aortic stenosis population.

BACKGROUND: Aortic valve bypass (AVB; apicoaortic conduit) surgery relieves aortic stenosis (AS) by shunting blood from the apex of the left ventricle to the descending thoracic aorta through a valved conduit. We have performed AVB surgery as an alternative to conventional aortic valve replacement for high-risk AS patients. METHODS AND RESULTS: Between 2003 and 2007, 31 high-risk AS patients were treated with AVB surgery. Twenty-two patients (71%) were undergoing reoperation with patent coronary bypass grafts, and 5 (16%) had a porcelain ascending aorta. The average age was 81 years. Cardiopulmonary bypass was used for 19 of 31 patients (61%); the median duration of cardiopulmonary bypass was 19 minutes. Cross-clamp time for all patients was 0 minutes. Perioperative mortality was 13% (4 of 31 patients); no perioperative deaths occurred in the last 16 consecutive patients. One patient experienced a stroke related to intraoperative hypotension. No strokes have occurred during follow-up. Renal function was unchanged after AVB (preoperative creatinine, 1.3+/-0.5 mg/dL; postoperative creatinine, 1.2+/-0.5 mg/dL). The mean gradient across the native aortic valve decreased from 43.5+/-15 to 10.4+/-5.4 mm Hg. Echocardiographically determined conduit flow expressed as a percentage of total cardiac output was 72+/-12%. CONCLUSIONS: AVB surgery is an important therapeutic option for high-risk patients with symptomatic AS. Ventricular outflow is distributed in a predictable fashion between the conduit and the left ventricular outflow tract, and AVB surgery reliably relieves AS. Stroke and renal dysfunction were uncommon.