Management of severe ischemic cardiomyopathy: left ventricular assist device as destination therapy versus conventional bypass and mitral valve surgery

OBJECTIVES

Patients with severe ischemic cardiomyopathy (left ventricular ejection fraction <25%) and severe ischemic mitral regurgitation have a poor survival with medical therapy alone. Left ventricular assist device as destination therapy is reserved for patients who are too high risk for conventional surgery. We evaluated our outcomes with conventional surgery within this population and the comparative effectiveness of these 2 therapies.

METHODS

We identified patients who underwent conventional surgery or left ventricular assist device as destination therapy for severe ischemic cardiomyopathy (left ventricular ejection fraction <25%) and severe mitral regurgitation. The era for conventional surgery spanned from 1993 to 2009 and from 2007 to 2011 for left ventricular assist device as destination therapy. We compared baseline patient characteristics and outcomes in terms of end-organ function and survival.

RESULTS

A total of 88 patients were identified; 55 patients underwent conventional surgery (63%), and 33 patients (37%) received a left ventricular assist device as destination therapy. Patients who received left ventricular assist device as destination therapy had the increased prevalence of renal failure, inotrope dependency, and intra-aortic balloon support. Patients undergoing conventional surgery required longer ventilatory support, and patients receiving a left ventricular assist device required more reoperation for bleeding. Mortality rates were similar between the 2 groups at 30 days (7% in the conventional surgery group vs 3% in the left ventricular assist device as destination therapy group, P = .65) and at 1 year (22% in the conventional surgery group vs 15% in the left ventricular assist device as destination therapy group, P = .58). There was a trend toward improved survival in patients receiving a left ventricular assist device compared with the propensity-matched groups at 1 year (94% vs 71%, P = .171).

CONCLUSIONS

The operative mortality and early survival after conventional surgery seem to be acceptable. For inoperable or prohibitive-risk patients, left ventricular assist device as destination therapy can be offered with similar outcomes.

Decreased postoperative atrial fibrillation following cardiac transplantation: the significance of autonomic denervation

BACKGROUND

Endocardial ablation approaches targeting the retroatrial cardiac ganglia to treat atrial fibrillation (AF) have been proposed. However, the potential value using this approach is unknown. Disruption of the autonomic inputs with orthotropic heart transplant (OHT) provides a unique opportunity to study the effects of autonomic innervation on AF genesis and maintenance. We hypothesized that due to denervation, the risk of postoperative AF would be lower following OHT compared to surgical maze even though both groups get isolation of the pulmonary veins.

METHODS AND RESULTS

We reviewed 155 OHTs (mean age 52 ± 11 years, 72% males) and used 1:1 age-, sex-, and date-of-surgery-matched two control groups from patients undergoing surgical maze or only coronary artery bypass grafting (CABG). Using conditional logistic regression we compared the odds of AF within 2 weeks following OHT versus controls. Postoperative AF occurred in 10/155 (6.5%) OHT patients. The conditional odds of postoperative AF were lower for OHT as compared to controls (vs maze: odds ratio [OR] 0.27 [95% confidence interval (CI) 0.13-0.57], vs CABG: OR 0.38 [0.17-0.81], P = 0.003; and on additional adjustment for left atrial enlargement, vs maze: OR 0.28 [0.13-0.60], vs CABG: OR 0.14 [0.04-0.47], P = 0.0009).

CONCLUSIONS

Risk of postoperative AF is significantly lower with OHT as in comparison to surgical maze. As both surgeries entail isolation of the pulmonary veins but only OHT causes disruption of autonomic innervation, this observation supports a mechanistic role of autonomic nervous system in AF. The benefit of targeting the cardiac autonomic system to treat AF needs further investigation.

Predictive value of the model for end-stage liver disease score in patients undergoing left ventricular assist device implantation

Axial flow left ventricular assist device (LVAD) implantation is an effective therapy for patients with advanced heart failure. As the preoperative hepatic and renal function play a critical role in determining adverse events after LVAD implantation, we analyzed the predictive role of the model for end-stage liver disease (MELD) score in determining in-hospital mortality after surgery. One hundred twenty-six patients underwent implant of an LVAD at our institution. Their individual preoperative MELD scores and perioperative total blood product usage (TBPU) were calculated. As LVAD implant as a reoperation is known to influence postoperative bleeding and mortality independently, the patients were divided into group I (first cardiac surgery) and group II (reoperative surgery). Group I: LVAD implantation was performed in 68/126 (54%) patients as their first cardiac surgery. The mean MELD score was 16.3 ± 6. Median TBPU for this group was 20.7 (0, 135) units. Inhospital mortality/30-day mortality was 4/68 (5.8%). Increasing MELD score (c-statistic = 0.88) and TBPU were found to be predictors of early mortality. An increasing MELD score was associated with more TBPU (p < 0.01) with a 10.9 ± 3 TBPU increase per a 10 unit rise in the MELD score. Group II: Of the 126 patients, 58 (46%) underwent LVAD implantation as a reoperation. Mean MELD score for these patients was 16 ± 5. Inhospital mortality/30-day mortality in this group was 12% and median TBPU was 30 (4,153) units. The MELD score was not predictive of inhospital mortality in these patients (p = 0.97). The MELD score is predictive of early mortality in patients undergoing LVAD implantation as their first cardiac surgery. Use of this score to select patients for LVAD implantation may be appropriate.

Durability of central aortic valve closure in patients with continuous flow left ventricular assist devices

BACKGROUND

A competent aortic valve is essential to providing effective left ventricular assist device support. We have adopted a practice of central aortic valve closure by placing a simple coaptation stitch at left ventricular assist device implantation in patients with significant aortic insufficiency. We conducted a follow-up study to evaluate the efficacy and durability of this procedure.

METHODS

The study included patients who had undergone continuous flow left ventricular assist device implantation. The patients were divided into 2 groups, those who did not require any aortic procedure because the valve was competent and those who underwent central aortic valve closure for mild or greater aortic regurgitation. The clinical endpoints were mortality, progression or recurrence of aortic insufficiency, and reoperation for aortic valve pathologic features. Aortic insufficiency was measured qualitatively from mild to severe on a scale of 0 to 5.

RESULTS

A total of 123 patients received continuous flow left ventricular assist devices from February 2007 to August 2011. Of those, 18 (15%) underwent central aortic valve closure at left ventricular assist device implantation because of significant aortic insufficiency (1.8 ± 1.4) and 105 who did not (competent aortic valve, 0.15 ± 0.43; P < .01). At follow-up (median, 312 days; range, 0-1429 days), the mean aortic insufficiency score remained low for the patients with central aortic valve closure (0.27 ± 0.46) in contrast to those without central aortic valve closure who experienced aortic insufficiency progression (0.78 ± 0.89; P = .02). In addition, the proportion of patients with more than mild aortic insufficiency was significantly less in the central aortic valve closure group (0% vs 18%; P = .05). The patients in the central aortic valve closure group were significantly older and had a greater incidence of renal failure at baseline. The 30-day mortality was greater in the central aortic valve closure group, but the late survival was similar between the 2 groups. No reoperations were required for recurrent aortic insufficiency.

CONCLUSIONS

The results of our study have shown that repair of aortic insufficiency with a simple central coaptation stitch is effective and durable in left ventricular assist device-supported patients, with follow-up extending into 2 years. Although aortic insufficiency progressed over time in those with minimal native valve regurgitation initially, no such progression was noted in those with central aortic valve closure. Additional investigation is needed to evaluate whether prophylactic central aortic valve closure should be performed at left ventricular assist device implantation to avoid problematic aortic regurgitation developing over time, in particular in patients undergoing left ventricular assist device implantation for life-long (destination therapy) support.

Concomitant tricuspid valve repair or replacement during left ventricular assist device implant demonstrates comparable outcomes in the long term

INTRODUCTION

Severe tricuspid regurgitation (TR) is present in nearly half the patients undergoing implant of a left ventricular assist device (LVAD) and its correction confers better long-term outcome.

AIM

To compare the early and late results of tricuspid valve repair (TVrpr) or replacement (TVR) with LVAD implant.

PATIENT AND METHODS

Sixty-four from a cohort of 126 patients had a concomitant tricuspid valve procedure; 48 (75%) underwent a TVrpr whereas 16 (25%) had TVR. All preoperative hemodynamic parameters including the mean TR grade (TVrpr; 3.6 vs. TVR; 3.7) were comparable (p = 0.7). The mean TR grade was 1.6 ± 1.5 for the remaining 62 patients who did not have a concomitant tricuspid valve procedure, with 4/62 (6%) having severe TR (p < 0.0001).

RESULTS

Cardiopulmonary bypass time was longer for patients undergoing TVR (p = 0.01). There was a significant reduction in right atrial pressure for the entire cohort (p < 0.01) and the postoperative right atrial pressure was not statistically different between TVrpr (13.6 ± 4.6) and TVR (11.6 ± 4.3; p = 0.6. Postoperative intensive care unit stay was comparable as was the duration of inotropic support (p = 0.5) or need for temporary right ventricular mechanical support. In-hospital mortality (12%) was not different between groups. The mean time for LVAD support was 12.3 ± 9.71 months and the last transthoracic echocardiographic examination was performed at mean intervals of 13.8 ± 10.8 months (TVrpr) and 11.8 ± 7.6 months (TVR; p = 0.47). Reduction in TR grade was similar between groups (p = 0.27). Late mortality (p = 1.00) was comparable in both groups. Using log-rank analysis, there was no significant difference in the estimated survival between TVrpr and TVR (p = 0.88).

CONCLUSION

TVrpr repair at the time of LVAD implant is effective in correcting TR even at the end of one year of follow-up. The choice to repair or replace does not affect the clinical outcome.

Concomitant tricuspid valve repair or replacement during left ventricular assist device implant demonstrates comparable outcomes in the long term

INTRODUCTION

Severe tricuspid regurgitation (TR) is present in nearly half the patients undergoing implant of a left ventricular assist device (LVAD) and its correction confers better long-term outcome.

AIM

To compare the early and late results of tricuspid valve repair (TVrpr) or replacement (TVR) with LVAD implant.

PATIENT AND METHODS

Sixty-four from a cohort of 126 patients had a concomitant tricuspid valve procedure; 48 (75%) underwent a TVrpr whereas 16 (25%) had TVR. All preoperative hemodynamic parameters including the mean TR grade (TVrpr; 3.6 vs. TVR; 3.7) were comparable (p = 0.7). The mean TR grade was 1.6 ± 1.5 for the remaining 62 patients who did not have a concomitant tricuspid valve procedure, with 4/62 (6%) having severe TR (p < 0.0001).

RESULTS

Cardiopulmonary bypass time was longer for patients undergoing TVR (p = 0.01). There was a significant reduction in right atrial pressure for the entire cohort (p < 0.01) and the postoperative right atrial pressure was not statistically different between TVrpr (13.6 ± 4.6) and TVR (11.6 ± 4.3; p = 0.6. Postoperative intensive care unit stay was comparable as was the duration of inotropic support (p = 0.5) or need for temporary right ventricular mechanical support. In-hospital mortality (12%) was not different between groups. The mean time for LVAD support was 12.3 ± 9.71 months and the last transthoracic echocardiographic examination was performed at mean intervals of 13.8 ± 10.8 months (TVrpr) and 11.8 ± 7.6 months (TVR; p = 0.47). Reduction in TR grade was similar between groups (p = 0.27). Late mortality (p = 1.00) was comparable in both groups. Using log-rank analysis, there was no significant difference in the estimated survival between TVrpr and TVR (p = 0.88).

CONCLUSION

TVrpr repair at the time of LVAD implant is effective in correcting TR even at the end of one year of follow-up. The choice to repair or replace does not affect the clinical outcome.

Multiple arterial grafts improve late survival of patients undergoing coronary artery bypass graft surgery: analysis of 8622 patients with multivessel disease

BACKGROUND

Use of the left internal mammary artery (LIMA) in multivessel coronary artery disease improves survival after coronary artery bypass graft surgery; however, the survival benefit of multiple arterial (MultArt) grafts is debated.

METHODS AND RESULTS

We reviewed 8622 Mayo Clinic patients who had isolated primary coronary artery bypass graft surgery for multivessel coronary artery disease from 1993 to 2009. Patients were stratified by number of arterial grafts into the LIMA plus saphenous veins (LIMA/SV) group (n=7435) or the MultArt group (n=1187). Propensity score analysis matched 1153 patients. Operative mortality was 0.8% (n=10) in the MultArt and 2.1% (n=154) in the LIMA/SV (P=0.005) group, which was not statistically different (P=0.996) in multivariate analysis or the propensity-matched analysis (P=0.818). Late survival was greater for MultArt versus LIMA/SV (10- and 15-year survival rates were 84% and 71% versus 61% and 36%, respectively [P<0.001], in unmatched groups and 83% and 70% versus 80% and 60%, respectively [P=0.0025], in matched groups). MultArt subgroups with bilateral internal mammary artery/SV (n=589) and bilateral internal mammary artery only (n=271) had improved 15-year survival (86% and 76%; 82% and 75% at 10 and 15 years [P<0.001]), and patients with bilateral internal mammary artery/radial artery (n=147) and LIMA/radial artery (n=169) had greater 10-year survival (84% and 78%; P<0.001) versus LIMA/SV. In multivariate analysis, MultArt grafts remained a strong independent predictor of survival (hazard ratio, 0.79; 95% confidence interval, 0.66-0.94; P=0.007).

CONCLUSIONS

In patients undergoing isolated coronary artery bypass graft surgery with LIMA to left anterior descending artery, arterial grafting of the non-left anterior descending vessels conferred a survival advantage at 15 years compared with SV grafting. It is still unproven whether these results apply to higher-risk subgroups of patients.

Do pericardial bioprostheses improve outcome of elderly patients undergoing aortic valve replacement?

BACKGROUND

Pericardial bioprostheses have favorable echocardiographic hemodynamics in the aortic position compared with porcine valves; however, there are few data comparing clinical outcomes. Our objective was to assess the late results of the two valve types.

METHODS

We reviewed 2,979 patients aged 65 years or older undergoing aortic valve replacement with pericardial (n=1,976) or porcine (n=1,003) prostheses between January 1993 and December 2007. The most common pericardial prostheses were Carpentier-Edwards Perimount and Mitroflow, and the most common porcine valves were Medtronic Mosaic, Carpentier-Edwards, Hancock modified orifice, and St. Jude Biocor. Follow-up extended to a maximum of 16 years (mean, 5.2±3.5 years).

RESULTS

Survival at 5, 10 and 12 years was, respectively, 68%, 33%, and 21% overall, was 68%, 30%, and 16% for patients with pericardial bioprosthesis, and was 69%, 38% and 27% for the porcine group. In a multivariate model, long-term survival was reduced in patients with diabetes, renal failure, prior myocardial infarction, congestive heart failure, and older age, but late survival was not higher in the pericardial valve group. Overall freedom from reoperation was 96%, 92%, and 90% at 5, 10, and 12 years, and freedom from explant was 98%, 96%, and 94% during the same period. The reason for explant was structural valve deterioration in 50 patients (2%).

CONCLUSIONS

Despite the better hemodynamic performance documented in prior investigations, pericardial valves do not confer any survival advantage over porcine valves in patients aged 65 years or older undergoing aortic valve replacement.

Seligman's Theory of Attributional Style: Optimism, Pessimism, and Quality of Life after Heart Transplant

Context—

Posttransplant quality of life can be significantly affected by personality characteristics identified before transplant.

Objective—

Although overall quality of life in heart transplant patients improves after transplant, many studies reveal poorer mental health outcomes after transplant. We aimed to determine whether transplant recipients with an optimistic explanatory style had improved quality of life, fewer depressive symptoms, and increased survival.

Design—

We reviewed 68 patients who had completed a Minnesota Multiphasic Personality Inventory a mean of 2 years before transplant and examined associations between scores on the Optimism-Pessimism scale, survival rates, and results from the Health Status Questionnaire nearly 4 years after transplant.

Results—

Optimism was significantly associated with higher quality of life even after age (at the time of transplant), sex, depression score before transplant, time from the personality inventory to transplant, and time from transplant to the Health Status Questionnaire were controlled for. Furthermore, a pessimistic explanatory style was significantly associated with self-reported depressive symptoms, even after depression before transplant was adjusted for. Neither optimism nor pessimism was associated with length of survival.

Conclusions—

Pretransplant patients with a pessimistic explanatory style reported depressive symptoms nearly 5 years later. Furthermore, over the same time span, patients with an optimistic explanatory style described a significantly higher quality of life than the pessimists described.

Sirolimus as primary immunosuppression attenuates allograft vasculopathy with improved late survival and decreased cardiac events after cardiac transplantation

BACKGROUND

We retrospectively analyzed the potential of sirolimus as a primary immunosuppressant in the long-term attenuation of cardiac allograft vasculopathy progression and the effects on cardiac-related morbidity and mortality.

METHODS AND RESULTS

Forty-five cardiac transplant recipients were converted to sirolimus 1.2 years (0.2, 4.0) after transplantation with complete calcineurin inhibitor withdrawal. Fifty-eight control subjects 2.0 years (0.2, 6.5 years) from transplantation were maintained on calcineurin inhibitors. Age, sex, ejection fraction, and time from transplantation to baseline intravascular ultrasound study were not different (P>0.2 for all) between the groups; neither were secondary immunosuppressants and use of steroids. Three-dimensional intravascular ultrasound studies were performed at baseline and 3.1 years (1.3, 4.6 years) later. Plaque index progression (plaque volume/vessel volume) was attenuated in the sirolimus group (0.7±10.5% versus 9.3±10.8%; P=0.0003) owing to reduced plaque volume in patients converted to sirolimus early (<2 years) after transplantation (P=0.05) and improved positive vascular remodeling (P=0.01) in patients analyzed late (>2 years) after transplantation. Outcome analysis in 160 consecutive patients maintained on 1 therapy was performed regardless of performance of intravascular ultrasound examinations. Five-year survival was improved with sirolimus (97.4±1.8% versus 81.8±4.9%; P=0.006), as was freedom from cardiac-related events (93.6±3.2% versus 76.9±5.5%; P=0.002).

CONCLUSIONS

Substituting calcineurin inhibitor with sirolimus as primary immunosuppressant attenuates long-term cardiac allograft vasculopathy progression and may improve long-term allograft survival owing to favorable coronary remodeling. Because of the lack of randomization and retrospective nature of our analysis, the differences in outcome should be interpreted cautiously, and prospective clinical trials are required.

Combined heart and kidney transplantation provides an excellent survival and decreases risk of cardiac cellular rejection and coronary allograft vasculopathy

BACKGROUND

We analyzed the results of combined heart-kidney transplantation (CHKTx) over a 10-year period.

METHODS

Between September 1996 and May 2007 at Mayo Clinic, 12 patients (age 52 ± 12.2 years) underwent CHKTx as a simultaneous procedure in 10 recipients and as a staged procedure in two recipients with unstable hemodynamics after heart transplantation.

RESULTS

There was no operative mortality. Patient survival rates for the CHKTx recipients at 1 and 3 months and 6 years were 91%, 83%, and 83% and did not differ from isolated heart transplantation (IHTx) recipients (97%, 95%, and 79%, P = 0.61). The freedom from cardiac allograft rejection (≥ grade 2) at 3 months was 73% for CHKTx and had not changed during further follow-up; for IHTx, freedom from rejection at 3 months and 1 and 6 years was 61%, 56%, and 42% (P = .08). Heart and renal allograft survival was 100% with and left ventricular ejection fraction 66% ± 8.4% and glomerular filtration rate 61 ± 25 at last follow-up. There were no signs of cardiac allograft vasculopathy in the CHKTx recipients.

CONCLUSION

CHKTx yields favorable long-term outcome, with a low incidence of cardiac rejection and vasculopathy. Simultaneous CHKTx appears feasible, if hemodynamics is satisfactory. This approach expands the selection criteria for transplantation in patients with coexisting end-stage cardiac and renal disease.

Robotic mitral valve repair for all categories of leaflet prolapse: improving patient appeal and advancing standard of care

OBJECTIVE

To characterize the early outcomes of robotic mitral valve (MV) repair using standard open techniques.

PATIENTS AND METHODS

We prospectively studied 100 patients with severe mitral regurgitation due to leaflet prolapse who underwent robot-assisted MV repair using conventional open-repair techniques between January 1, 2008, and December 31, 2009, at Mayo Clinic, Rochester, MN.

RESULTS

The mean age of the patients was 53.9 years; 77 patients (77%) were male. Fifty-nine patients (59%) had posterior leaflet prolapse, 38 (38%) had bileaflet disease, and 3 (3%) had isolated anterior leaflet prolapse. Median cross-clamp and bypass times decreased significantly during the course of the study (P<.001). Median postoperative ventilation time was 0 hours for the last 25 patients, with most patients extubated in the operating room. No deaths occurred. Reexploration for postoperative bleeding occurred in 1 patient (1%); 3 patients (3%) required percutaneous coronary intervention. Median hospital stay was 3 days. One patient (1%) underwent mitral reoperation for annuloplasty band dehiscence. Residual regurgitation was mild or less in all patients at dismissal and 1 month postoperatively. Significant reverse remodeling occurred by 1 month, including decreased left ventricular end-diastolic diameter (-7.2 mm; P<.001) and left ventricular end-diastolic volume (-61.0 mL;P<.001).

CONCLUSION

Robot-assisted MV repair using proven, conventional open-repair techniques is reproducible and safe and hastens recovery for all categories of leaflet prolapse. One month after surgery, significant regression in left ventricular size and volume is evident.

Aortic Valve Replacement in the Elderly

Background—

Few data exist on long-term outcomes of elderly patients after aortic valve replacement. We evaluated latest follow-up information for patients ≥70 years of age after aortic valve replacement.

Methods and Results—

Late overall survival of 2890 consecutive patients ≥70 years of age who underwent aortic valve replacement between January 1993 and December 2007 was reviewed retrospectively, analyzed, and stratified by preoperative and intraoperative variables. Observed 5-, 10-, and 15-year late postoperative survival was lower than generally expected (68%, 34%, and 8% versus 70%, 42%, and 20%, respectively; P <0.001). Independent predictors of late death included older age, renal failure, diabetes mellitus, stroke, myocardial infarction, immunosuppression, prior coronary artery bypass grafting, implanted pacemaker, lower ejection fraction, hypertension, and New York Heart Association class III or IV. After stratification by age–comorbidity risk score, 10-year survival for the lowest-risk group (n=946 [33%]) was similar to expected survival (55% versus 55%; P =0.50), but for the highest-risk group (n=564 [20%]), survival was significantly lower than expected (9% versus 26%; P <0.001). For 229 pairs of propensity-matched patients with mechanical or biological prostheses, survival was not significantly different (67%, 40%, and 19% versus 71%, 45%, and 7% at 5, 10, and 15 years, respectively; P =0.81). Structural deterioration of bioprostheses occurred in 64 patients (2.4%).

Conclusions—

Survival of elderly patients after aortic valve replacement is influenced by age and preoperative comorbidities; 33% at lowest risk had overall survival similar to that of an age- and sex-matched general population. There was no sufficient evidence that valve type affected survival. Structural deterioration of aortic bioprostheses was rare.

Risk of recurrent gastrointestinal bleeding after aortic valve replacement in patients with Heyde syndrome

OBJECTIVE

We sought to evaluate the effectiveness of aortic valve replacement for reducing gastrointestinal bleeding in patients with Heyde syndrome, in whom gastrointestinal bleeding is associated with intestinal angiodysplasia and aortic valve stenosis.

METHODS

We conducted a retrospective review of patients treated at the Mayo Clinic between 1971 and 2007 for gastrointestinal bleeding and intestinal angiodysplasia who later underwent aortic valve replacement for severe aortic valve stenosis. We analyzed early and late outcomes, including recurrent gastrointestinal hemorrhage.

RESULTS

Fifty-seven patients (39 men and 18 women) were identified. At operation, the median age of patients was 75 years. Intestinal angiodysplasia occurred most commonly in the duodenum and right side of the colon. Before aortic valve replacement, the mean number of bleeding episodes was 12 per patient-year; 48 patients (84%) required blood transfusions. Bioprosthetic valves were used in 47 patients. During follow-up extending to 15 years, 45 patients (79%) had no recurrence of bleeding. In patients who experienced recurrent bleeding, the episodes were reduced from a mean ± standard deviation of 4.7 ± 7 episodes per patient-year to 1.9 ± 2 per patient-year. Recurrent bleeding occurred only in patients with lesions of the duodenum or right colon. Among patients who received bioprostheses, the overall risk of recurrent bleeding was 15%, lower than the 50% risk of subsequent gastrointestinal bleeding with mechanical prostheses.

CONCLUSIONS

Aortic valve replacement seems to decrease the risk of gastrointestinal bleeding in patients with Heyde syndrome and is curative in approximately 80%. Although rates of recurrent bleeding were not significantly different between the 2 prosthetic valve types, the higher risk of bleeding in patients receiving warfarin makes bioprosthetic valves the valve of choice for most patients.

Ablation of atrial fibrillation: comparison of catheter-based techniques and the Cox-Maze III operation

BACKGROUND

Catheter-based ablation is often recommended for treatment of atrial fibrillation (AF), but there are no data that directly compare late results to those of the Cox-Maze procedure. Although catheter ablation avoids operation, lack of reliable transmurality may reduce effectiveness. We compared clinical outcomes of the cut-and-sew Cox-Maze procedure with catheter ablation.

METHODS

Between January 1993 and October 2007, 97 patients aged 25 to 80 years underwent an isolated cut-and-sew Cox-Maze procedure. Patients were matched 1:2 according to age, sex, and AF type, with 194 patients undergoing catheter-based ablation for lone AF.

RESULTS

At last follow-up, 82% of patients who underwent the Cox-Maze procedure were free of AF and had stopped taking antiarrhythmic medications compared with 55% of patients who underwent ablation (p<0.001). When analyzed as a time-related event, freedom from recurrent AF was 87% 5 years after the Cox-Maze procedure compared with 28% after catheter ablation (p<0.001). Late warfarin anticoagulation was required in 12% of patients who underwent the Cox-Maze procedure compared with 55% of patients who underwent ablation (p<0.001), and use of antiarrhythmic medications during follow-up was significantly higher in patients who underwent ablation (68% versus 15%, p<0.001). Forty-one patients (24%) required repeated ablation procedure and 9 required a second repeated ablation.

CONCLUSIONS

Compared with catheter-based ablation, the Cox-Maze procedure results in greater freedom from AF and less medical treatment with antiarrhythmic drugs and warfarin anticoagulation during follow-up.

Clinical accuracy of RIFLE and Acute Kidney Injury Network (AKIN) criteria for acute kidney injury in patients undergoing cardiac surgery

Introduction

The RIFLE (risk, injury, failure, loss of kidney function, and end-stage renal failure) classification for acute kidney injury (AKI) was recently modified by the Acute Kidney Injury Network (AKIN). The two definition systems differ in several aspects, and it is not clearly determined which has the better clinical accuracy.

Methods

In a retrospective observational study we investigated 4,836 consecutive patients undergoing cardiac surgery with cardiopulmonary bypass from 2005 to 2007 at Mayo Clinic, Rochester, MN, USA. AKI was defined by RIFLE and AKIN criteria.

Results

Significantly more patients were diagnosed as AKI by AKIN (26.3%) than by RIFLE (18.9%) criteria (P < 0.0001). Both definitions showed excellent association to outcome variables with worse outcome by increased severity of AKI (P < 0.001, all variables). Mortality was increased with an odds ratio (OR) of 4.5 (95% CI 3.6 to 5.6) for one class increase by RIFLE and an OR of 5.3 (95% CI 4.3 to 6.6) for one stage increase by AKIN. The multivariate model showed lower predictive ability of RIFLE for mortality. Patients classified as AKI in one but not in the other definition set were predominantly staged in the lowest AKI severity class (9.6% of patients in AKIN stage 1, 2.3% of patients in RIFLE class R). Potential misclassification of AKI is higher in AKIN, which is related to moving the 48-hour diagnostic window applied in AKIN criteria only. The greatest disagreement between both definition sets could be detected in patients with initial postoperative decrease of serum creatinine.

Conclusions

Modification of RIFLE by staging of all patients with acute renal replacement therapy (RRT) in the failure class F may improve predictive value. AKIN applied in patients undergoing cardiac surgery without correction of serum creatinine for fluid balance may lead to over-diagnosis of AKI (poor positive predictive value). Balancing limitations of both definition sets of AKI, we suggest application of the RIFLE criteria in patients undergoing cardiac surgery.