Robotic-assisted mitral valve repair: surgical technique

Robotic-assisted mitral valve repair represents the least invasive surgical approach currently available for anatomical mitral valve repair in patients with myxomatous mitral valve disease. Standard mitral valve repair techniques utilized during conventional sternotomy/right thoracotomy are exactly replicated with the robotic instrumentation through 1-2 cm port-like incisions with superior 3D visualization. This is performed on cardiopulmonary bypass by peripheral cannulation of the femoral vessels/right internal jugular vein. The ascending aorta is occluded with a transthoracic aortic cross-clamp. Antegrade cardioplegia is delivered centrally into the aortic root through a cardioplegia vent catheter. By replicating conventional mitral valve repair done via an open sternotomy approach, the quality of mitral valve repair is ensured while providing the patients with advantages of less invasive surgery including shorter hospital stay, rapid recovery and return to normal activities, less blood transfusion, superior cosmesis and complete elimination of sternotomy-related morbidities such as deep sternal wound infection and sternal dehiscence. We reviewed the first consecutive 200 patients undergoing robotic mitral valve repair at Mayo Clinic Rochester between 24 January 2008 and 28 January 2011. Successful mitral valve repair was completed in all patients. There were no early (30-day) deaths. One patient suffered a stroke (0.5%). One patient required reoperation for bleeding (0.5%). Two patients (1%) required reoperation for recurrent mitral regurgitation. Twelve patients (6%) required transfusion of allogeneic blood products. We have noted a significant reduction in operative times and resource utilization over time.

Cardiac transplantation for radiation-induced cardiomyopathy: the Mayo Clinic experience

BACKGROUND

High-dose radiotherapy to the mediastinum for the treatment of malignancies causes injury to the intrathoracic organs. Coronary artery disease, valvular dysfunction, cardiomyopathy, and chronic constrictive pericarditis are common cardiovascular sequelae during long-term follow-up. Cardiac transplantation is indicated for the surgical treatment of heart failure due to radiation-induced end-stage cardiac disease.

METHODS

A retrospective study of radiation-induced cardiomyopathy requiring cardiac transplantation was undertaken from December 1992 to August 2010.

RESULTS

Twelve patients (7 men, 5 women), with a mean age of 47.4 years, underwent orthotopic cardiac transplantation. Redo cardiac operations were performed in 9 patients. Lymphoma was the primary malignancy in all patients. Adjuvant chemotherapy was used in 9 patients, and splenectomy was performed in 7. Restrictive cardiomyopathy (n = 8) was the predominant diagnosis. Restrictive lung disease was present in 10 patients (83%). Postoperative chronic kidney injury developed in 3 patients (25%). Hospital mortality was 8.3%. Survival at 1, 5, and 10 years was 91.7%, 75%, and 46.7%, respectively. The overall mean follow-up was 7.7 years (median, 6.1; range, 1.8 to 16.4 years). Late respiratory failure accounted for 3 deaths.

CONCLUSIONS

Cardiac transplantation provides satisfactory medium-term to long-term outcome in patients with radiation-induced cardiomyopathy. Secondary malignancies, kidney injury, and respiratory failure contribute to significant postoperative morbidity and death.

The prognostic impact of concomitant coronary artery bypass grafting during aortic valve surgery: implications for revascularization in the transcatheter era

OBJECTIVE

Clinicians may give greater consideration to medical management versus coronary artery bypass grafting (CABG) for coronary artery disease (CAD) at the time of aortic valve intervention. We evaluated the prognostic impact of revascularization strategy during aortic valve replacement (AVR).

METHODS

We studied 1308 consecutive patients with significant CAD (≥50% stenosis) undergoing AVR with or with out CABG between 2001 and 2010. Late mortality and its determinants were analyzed using multivariable Cox models.

RESULTS

Patients undergoing CABG (n = 1043; 18%) had more frequent angina (50% vs 26%; P < .001), left ventricular dysfunction (22% vs 14%; P = .003), advanced (>70% stenosis) CAD (85% vs 48%; P < .001), and incidence of triple-vessel/left-main CAD (44% vs 8%; P < .001). Whereas operative mortality was comparable between patients undergoing AVR plus CABG versus isolated AVR (2.9% vs 3.0%; P = .90), 5-year (72% vs 64%) and 8-year (50% vs 39%) survival was higher following CABG (P = .007). Adjusting for older age (hazard ratio [HR], 1.28 per 5 years), female sex (HR, 1.23), peripheral vascular disease (HR, 1.71), New York Heart Association functional class III to IV (HR, 1.48), and diabetes (HR, 1.50) concomitant CABG at AVR reduced late mortality risk by more than one-third (HR, 0.62, 95% confidence interval, 0.49-0.79; P < .001). CABG continued to confer a survival advantage in patients with moderate (50%-70%) (HR, 0.62; P = .02) and severe (>70%) CAD (HR, 0.62; P = .002).

CONCLUSIONS

In patients undergoing AVR with coexistent CAD, concomitant CABG reduces risk of late death by more than one-third, without augmenting operative mortality. This survival advantage persists in moderate (50% to 70%) and severe (>70%) CAD. These findings underline the prognostic importance of revascularization in this population and should influence decisions regarding revascularization strategy in patients undergoing transcatheter valve therapy.

Healing high-risk sternotomy incisions: interrupted suture closure and negative pressure wound therapy

High-risk sternotomy incisions represent a challenge at the time of wound closure. We present an alternate wound closure technique that can be used in high-risk sternotomy incisions and consists of a combination of space-obliterating sutures and negative pressure (suction using wound VAC) therapy.

Influence of mitral valve repair versus replacement on the development of late functional tricuspid regurgitation

OBJECTIVES

To study the determinants of functional tricuspid regurgitation (TR) progression after surgical correction of mitral regurgitation, including the influence of mitral valve (MV) repair (MVr) versus replacement (MVR) for degenerative mitral regurgitation.

METHODS

From January 1995 to January 2006, 747 adults with MV prolapse underwent isolated MVr (n=683) or MVR (n=64; mechanical in 32). The mean age was 60.8 years, and 491 were men (66.0%). Moderate preoperative functional TR was present in 115 (15.4%). The MVR group had a greater likelihood of New York Heart Association class III or IV (75.0% vs 34.4%, P<.001), atrial fibrillation (20.3% vs 8.3%, P=.002), a lower left ventricular ejection fraction (61.0% vs 65.2%, P<.003), and a higher pulmonary artery pressure (50.1 vs 41.2 mm Hg, P=.001). The patients were monitored for a mean of 6.9 years (MVr) or 7.7 years (MVR; P=.075).

RESULTS

During late follow-up, no difference was found between the groups in the development of moderately severe or severe TR: 1 to 5 years (3.0% vs 3.3%, P=.91) and >5 years (6.1% vs 6.5%; P=.93). The univariate predictors of severe TR after 5 years were older age (hazard ratio [HR], 1.1; P=.011), female gender (HR, 6.86; P=.005), higher pulmonary artery pressure (HR, 1.05; P=.022), and larger left atrial size (HR, 2.11; P=.035). Two patients (0.26%) who had undergone initial MVr required reoperation for late functional TR. Another 2 patients had had the tricuspid valve addressed concurrent with reoperation for MVr failure. No tricuspid reoperations were required in the MVR group.

CONCLUSIONS

The risk of TR progression was low after MVr or MVR for MV prolapse. Timely MV surgery before the development of left atrial dilatation or pulmonary hypertension could further decrease the risk of TR progression during follow-up.

Cardiac and multiorgan transplantation for end-stage congenital heart disease

OBJECTIVE

To report our single-center experience with patients who had cardiac and multiorgan transplantation for end-stage congenital heart disease (CHD).

PATIENTS AND METHODS

We reviewed records for all patients with CHD who had undergone heart transplantation at Mayo Clinic, Rochester, Minnesota, from November 1, 1990, through June 30, 2012. Patients with cardiomyopathy were excluded, unless CHD was present.

RESULTS

Overall, 45 patients had cardiac transplantation for end-stage CHD (mean age, 26.1±18.4 years; range, 1 month to 65 years). Two patients (4%) had combined heart/liver transplantation; 1 (2%) had heart/kidney transplantation. Six patients (13%) had no previous cardiac operation; the remaining 39 patients had a mean of 3 (range, 1-8) previous cardiac operations. Patient survival (95% CI) at 1, 5, and 10 years was 89% (80%-98%), 89% (80%-98%), and 72% (56%-87%), respectively, while graft survival at 1, 5, and 10 years was 89% (80%-98%), 89% (80%-98%), and 61% (44%-78%), respectively. During the same era, the International Society for Heart & Lung Transplantation reported that survival in patients undergoing transplant for non-congenital diagnoses was 85%, 72%, and 56%, respectively. Over a mean follow-up of 8.7±6.2 years, rejection requiring treatment was documented in 35 patients (78%). Eleven patients (24%) have been diagnosed with neoplasia (8 skin, 1 blood, 1 lymph, and 1 other), and 3 patients (7%) have required retransplantation. Four patients (9%) have developed significant coronary vasculopathy; 1 successfully underwent retransplantation, and 3 died 6, 8, and 14 years after transplantation.

CONCLUSION

With appropriate patient selection and posttransplant monitoring, survival has improved for patients with complex end-stage CHD. Multiorgan transplantation is an option for selected patients with CHD.

Frailty and outcomes after implantation of left ventricular assist device as destination therapy

BACKGROUND

Frailty is recognized as a major prognostic indicator in heart failure. There has been interest in understanding whether pre-operative frailty is associated with worse outcomes after implantation of a left ventricular assist device (LVAD) as destination therapy.

METHODS

Patients undergoing LVAD implantation as destination therapy at the Mayo Clinic, Rochester, Minnesota, from February 2007 to June 2012, were included in this study. Frailty was assessed using the deficit index (31 impairments, disabilities and comorbidities) and defined as the proportion of deficits present. We divided patients based on tertiles of the deficit index (>0.32 = frail, 0.23 to 0.32 = intermediate frail, <0.23 = not frail). Cox proportional hazard regression models were used to examine the association between frailty and death. Patients were censored at death or last follow-up through October 2013.

RESULTS

Among 99 patients (mean age 65 years, 18% female, 55% with ischemic heart failure), the deficit index ranged from 0.10 to 0.65 (mean 0.29). After a mean follow-up of 1.9 ± 1.6 years, 79% of the patients had been rehospitalized (range 0 to 17 hospitalizations, median 1 per person) and 45% had died. Compared with those who were not frail, patients who were intermediate frail (adjusted HR 1.70, 95% CI 0.71 to 4.31) and frail (HR 3.08, 95% CI 1.40 to 7.48) were at increased risk for death (p for trend = 0.004). The mean (SD) number of days alive out of hospital the first year after LVAD was 293 (107) for not frail, 266 (134) for intermediate frail and 250 (132) for frail patients.

CONCLUSIONS

Frailty before destination LVAD implantation is associated with increased risk of death and may represent a significant patient selection consideration.

Cardiac transplantation after bridged therapy with continuous flow left ventricular assist devices

INTRODUCTION

Cardiac transplantation is an effective surgical therapy for end-stage heart failure. Patients (pts) may need to be bridged with a continuous flow left ventricular assist device (CF-LVAD) while on the transplant list as logistic factors like organ availability are unknown. Cardiac transplantation post-LVAD can be a surgically challenging procedure and outcome in these pts is perceived to be poorer based on experience with earlier generation pulsatile flow pumps. Data from a single institution comparing these pts with those undergoing direct transplantation in the present era of continuous flow device therapy are limited.

AIM

Evaluate results of cardiac transplantation in pts bridged with a CF-LVAD (BTx) and compare outcomes with pts undergoing direct transplantation (Tx) in a single institution.

RESULTS

From June 2007 till January 2012, 106 pts underwent cardiac transplantation. Among these, 37 (35%) pts (51±11 years; 85% male) were bridged with a CF-LVAD (BTx), while 70 (65%) comprised the Tx group (53±12 years; 72% males). The median duration of LVAD support was 227 (153,327) days. During the period of LVAD support, 10/37 (27%) pts were upgraded to status 1A and all were successfully transplanted. Median hospital stay in the BTx (14 days) was slightly longer than the Tx group (12 days) but not statistically significant (p=0.21). In-hospital mortality in the BTx (5%) and Tx (1%) were comparable (p=0.25). Estimated late survival in the BTx cohort was 94±7, 90±10 and 83±16% at the end of one, two and three years, respectively which was comparable to 97±4%, 93±6% and 89±9% for the Tx group (p=0.50).

CONCLUSION

Cardiac transplantation after LVAD implant can be performed with excellent results. Patients can be supported on the left ventricular assist device even for periods close to a year with good outcome after cardiac transplantation.

Hepatic and renal function with successful long-term support on a continuous flow left ventricular assist device

INTRODUCTION

Data regarding the long-term clinical effects of a continuous flow left ventricular assist device (CF-LVAD) on hepato-renal function is limited. Hence our aim was to assess changes in hepato-renal function over a one-year period in patients supported on a CF-LVAD.

METHODS

During the study period 126 patients underwent CF-LVAD implant. Changes in hepato-renal laboratory parameters were studied in 61/126 patients successfully supported on a CF-LVAD for period of one year. A separate cohort of a high-risk group (HCrB) of patients (56/126) with a serum creat>1.9 mg/dL (168 μmol/L) (75th percentile) or a serum bil>1.5 mg/dL (25.65 μmol/L) (75th percentile) was created. Changes in serum creatinine and bilirubin were analysed at regular intervals for this group along with the need for renal replacement therapy.

RESULTS

Baseline creatinine and blood urea nitrogen (BUN) for the entire cohort was 1.4[1.2,1.9 mg/dL] [123.7(106,168) μmol/L) and 27[20,39.5 mg/dL] [9.6(7.1,14.1) mmol/L] respectively. After an initial reduction at the end of one month [1(0.8,1.2) mg/dL; 88(70,105) μmol/L] (p<0.0001), a gradual increase was noted over the study period to reach (1.25[1.1,1.5] mg/dL; 106(97.2,132.6) μmol/L] (p=0.0003). The serum bilirubin normalised from a [1(0.7,1.55) mg/dL] [17(18.8,25.7) μmol/L) to 0.9(0.6,1.2)mg/dL [15.4(10.2,20.5) μmol/L] (p=0.0005) and continued to decline over one year. Improvement in the synthetic function of the liver was demonstrated by a rise in the serum albumin levels to reach 4.3[4.1,4.5] [43(41,45) gm/L] at the end of one year (p<0.0001). The baseline serum creatinine and bilirubin for the high-risk cohort (HCrB) was 1.9(1.3,2.4) mg/dL [168(115,212) μmol/L] and 1.7(1.00,2.4) mg/dL [29(17.1,68.4) μmol/L] respectively. The high-risk cohort (HCrB) demonstrated a trend towards higher 30-day mortality (p=0.06). While the need for temporary renal replacement therapy was higher in this cohort (16% vs. 4%; p=0.03), only 3% need it permanently. A significant reduction in creatinine was apparent at the end of one month [1.1(0.8,1.4) mg/dL; 97(70.7,123.7) μmol/L] (p<0.0001) and then remained stable at [1.3(1.1,1.5) mg/dL; 115(97,132.6) μmol/L]. Bilirubin demonstrated a 30% decline over one month and then remained low at [0.7(0.5,0.8) mg/dL; 62(44,70) μmol/L] p=0.0005 compared to the pre-operative baseline.

CONCLUSION

Hepato-renal function demonstrates early improvement and then remains stable in the majority of patients on continuous flow left ventricular assist device support for one year. High-risk patients demonstrate a higher 30-day mortality and temporary need for renal replacement therapy. Yet even in this cohort, improvement is present over a period of one year on the device, with a minimal need for permanent haemodialysis.

Empiric switch from calcineurin inhibitor to sirolimus-based immunosuppression in pediatric heart transplantation recipients

Sirolimus is used in heart transplant patients with CAV and CNI-induced nephropathy. However, little is known regarding the tolerability, rejection rate, and effect on renal function when used empirically in children. We describe our experience with the empiric use of a sirolimus-based immunosuppressive regimen in pediatric heart transplantation recipients. We reviewed records of patients in whom conversion was attempted to a CNI-free sirolimus-based regimen. Rejection episodes and measures of renal function were recorded. We attempted to convert 20 patients, of which 16 were successful. In total, six of 20 patients (30%) experienced adverse effects. Of the 16 converted, four patients converted to sirolimus due to CNI-induced disease (three nephropathy, one CAV), while 12 patients (mean age 5.5 yr, range 0.1-21 yr; 33% female; 33% with a history of congenital heart disease) were empirically switched to sirolimus at a mean of 2.3 yr after transplant. Follow-up was available for a mean of 2.5 yr after conversion (range 0.5-8.3 yr). The rate of rejection while taking CNIs was 0.18 rejection episodes per patient-year (total of five episodes), compared with 0.03 rejection episodes per patient-year (total of one episode) while on sirolimus. Renal function, in terms of GFR, significantly improved after sirolimus conversion at latest follow-up (from 86 ± 37 mL/min to 130 ± 49 mL/min, p = 0.02). Here, we demonstrate the potential benefit of empiric use of sirolimus in pediatric heart transplant patients in a CNI-free regimen. Larger and longer studies are needed to further clarify risks of rejection and adverse effect profiles.

Role of echocardiography in patients with intravascular hemolysis due to suspected continuous-flow LVAD thrombosis

OBJECTIVES

This study sought to characterize the echocardiographic findings of patients presenting with intravascular hemolysis (IVH) due to suspected continuous-flow left ventricular assist device (LVAD) pump thrombosis.

BACKGROUND

LVAD patients who develop pump thrombosis often present with IVH. Echocardiography may be able to detect device dysfunction in this setting.

METHODS

Continuous-flow LVAD patients presenting with IVH due to suspected pump thrombosis were identified. Patients underwent echocardiography with cannula Doppler flow velocity interrogation. Findings were compared with baseline and follow-up studies, and with 49 stable LVAD control patients.

RESULTS

Of 145 patients, 14 (10%) had IVH due to suspected pump thrombosis. The mean age was 55 ± 15 years, 93% were men, and 50% received LVAD as destination therapy. Mean duration between implantation and IVH was 231 ± 218 days. Eleven (79%) patients presented with hemoglobinuria, 9 (64%) with jaundice, and 5 (36%) with acute heart failure. Reduced cannula diastolic flow velocity and increased systolic/diastolic (S/D) flow velocity ratio were the only echocardiographic parameters significantly different from controls (outflow cannula 0.3 ± 0.2 m/s vs. 0.8 ± 0.3 m/s, p = 0.03, and 5.9 ± 2.8 vs. 1.7 ± 0.7, p < 0.01, respectively), and were worse for IVH patients with acute heart failure compared with those without (outflow cannula 0.2 ± 0.1 m/s vs. 0.5 ± 0.2 m/s, p = 0.04, and 7.2 ± 3.3 vs. 5.3 ± 2.0, p = 0.02, respectively). Outflow cannula diastolic flow velocity and S/D flow velocity ratio changed significantly from baseline (p = 0.01 and p < 0.01, respectively) in IVH patients, whereas systolic flow velocity did not change (p = 0.59). Odds ratios for outflow cannula diastolic flow velocity and S/D flow velocity ratio for predicting IVH were 0.60 (95% confidence interval [CI]: 0.51 to 0.73), p = 0.02, and 2.45 (95% CI: 2.37 to 2.52) p < 0.01, respectively. Corresponding inflow cannula values were similarly significant. Pump thrombosis was confirmed in 7 (50%) patients after LVAD retrieval.

CONCLUSIONS

Reduced cannula diastolic flow velocity and increased S/D flow velocity ratio identified continuous-flow LVAD dysfunction in patients with IVH due to suspected pump thrombosis better than other echocardiographic parameters.

Improving affordability through innovation in the surgical treatment of mitral valve disease

OBJECTIVE

To determine whether technically innovative cardiac surgical platforms (ie, robotics) deployed in conjunction with surgical process improvement (systems innovation) influence total hospital costs to address the concern that expanding adoption might increase health care expenses.

PATIENTS AND METHODS

We studied 185 propensity-matched patient pairs (370 patients) undergoing isolated conventional open vs robotic mitral valve repair with identical repair techniques and care teams between July 1, 2007, and January 31, 2011. Two time periods were considered, before the implementation of system innovations (pre-July 2009) and after implementation. Generalized linear mixed models were used to estimate the effect of the type of surgery on cost while adjusting for a time effect.

RESULTS

Baseline characteristics of the study patients were similar, and all patients underwent successful mitral valve repair with no early deaths. Median length of stay (LOS) for patients undergoing open repair was unchanged at 5.3 days (P=.636) before and after systems innovation implementation, and was lower for robotic patients at 3.5 and 3.4 days, respectively (P=.003), throughout the study. The overall median costs associated with open and robotic repair were $31,838 and $32,144, respectively (P=.32). During the preimplementation period, the total cost was higher for robotic ($34,920) than for open ($32,650) repair (P<.001), but during the postimplementation period, the median cost of robotic repair ($30,606) became similar to that of open repair ($31,310) (P=.876). The largest decrease in robotic cost was associated with more rapid ventilator weaning and shortened median intensive care unit LOS, from 22.7 hours before July 2009 to 9.3 hours after implementation of systems innovations (P<.001).

CONCLUSION

Following the introduction of systems innovation, the total hospital cost associated with robotic mitral valve repair has become similar to that for a conventional open approach, while facilitating quicker patient recovery and diminished utilization of in-hospital resources. These data suggest that innovations in techniques (robotics) along with care systems (process improvement) can be cost-neutral, thereby improving the affordability of new technologies capable of improving early patient outcomes.

Hepatic and renal function with successful long-term support on a continuous flow left ventricular assist device

INTRODUCTION

Data regarding the long-term clinical effects of a continuous flow left ventricular assist device (CF-LVAD) on hepato-renal function is limited. Hence our aim was to assess changes in hepato-renal function over a one-year period in patients supported on a CF-LVAD.

METHODS

During the study period 126 patients underwent CF-LVAD implant. Changes in hepato-renal laboratory parameters were studied in 61/126 patients successfully supported on a CF-LVAD for period of one year. A separate cohort of a high-risk group (HCrB) of patients (56/126) with a serum creat>1.9 mg/dL (168 μmol/L) (75th percentile) or a serum bil>1.5 mg/dL (25.65 μmol/L) (75th percentile) was created. Changes in serum creatinine and bilirubin were analysed at regular intervals for this group along with the need for renal replacement therapy.

RESULTS

Baseline creatinine and blood urea nitrogen (BUN) for the entire cohort was 1.4[1.2,1.9 mg/dL] [123.7(106,168) μmol/L) and 27[20,39.5 mg/dL] [9.6(7.1,14.1) mmol/L] respectively. After an initial reduction at the end of one month [1(0.8,1.2) mg/dL; 88(70,105) μmol/L] (p<0.0001), a gradual increase was noted over the study period to reach (1.25[1.1,1.5] mg/dL; 106(97.2,132.6) μmol/L] (p=0.0003). The serum bilirubin normalised from a [1(0.7,1.55) mg/dL] [17(18.8,25.7) μmol/L) to 0.9(0.6,1.2)mg/dL [15.4(10.2,20.5) μmol/L] (p=0.0005) and continued to decline over one year. Improvement in the synthetic function of the liver was demonstrated by a rise in the serum albumin levels to reach 4.3[4.1,4.5] [43(41,45) gm/L] at the end of one year (p<0.0001). The baseline serum creatinine and bilirubin for the high-risk cohort (HCrB) was 1.9(1.3,2.4) mg/dL [168(115,212) μmol/L] and 1.7(1.00,2.4) mg/dL [29(17.1,68.4) μmol/L] respectively. The high-risk cohort (HCrB) demonstrated a trend towards higher 30-day mortality (p=0.06). While the need for temporary renal replacement therapy was higher in this cohort (16% vs. 4%; p=0.03), only 3% need it permanently. A significant reduction in creatinine was apparent at the end of one month [1.1(0.8,1.4) mg/dL; 97(70.7,123.7) μmol/L] (p<0.0001) and then remained stable at [1.3(1.1,1.5) mg/dL; 115(97,132.6) μmol/L]. Bilirubin demonstrated a 30% decline over one month and then remained low at [0.7(0.5,0.8) mg/dL; 62(44,70) μmol/L] p=0.0005 compared to the pre-operative baseline.

CONCLUSION

Hepato-renal function demonstrates early improvement and then remains stable in the majority of patients on continuous flow left ventricular assist device support for one year. High-risk patients demonstrate a higher 30-day mortality and temporary need for renal replacement therapy. Yet even in this cohort, improvement is present over a period of one year on the device, with a minimal need for permanent haemodialysis.

Improved late survival with arterial revascularization

NEW CORONARY ARTERY REVASCULARIZATION STRATEGIES ARE DEVELOPING

improved quantification of coronary artery disease by the SYNTAX score, new-generation drug-eluting stents and increased use of stents for multivessel disease, ongoing evaluation of stents for left main disease, new strategies for minimally invasive coronary artery bypass grafting (CABG) including the use of robotic-assisted CABG, hybrid procedures, and off pump CABG. In comparisons of all these strategies, the impact on survival is arguably the most important parameter. It has long been accepted that using the left internal mammary artery (LIMA) to bypass the left anterior descending coronary artery (LAD) is the gold standard and may confer the survival advantage reported for CABG compared with percutaneous coronary intervention in the literature. The survival advantage of using additional arterial conduits as compared to the conventional use of LIMA with saphenous veins only has long been debated. Our study, which involved a large cohort of 8,622 patients with multivessel disease, followed over a long period of time, has shown that in primary isolated CABG surgery performed more than 15 years ago with the use of LIMA to the LAD, bypassing the non-LAD targets with at least 1 additional arterial graft, either the right internal mammary artery and/or the radial artery, was an independent predictor of increased survival during the following 15 years. The results were confirmed with both a propensity-matched analysis that included 1,153 patients in each group and a multivariate analysis that was able to control for all differences between the groups because of the power of the large cohort in this series. The significant survival advantage of coronary artery bypass surgery with the use of multiple arterial grafting cannot be ignored in patients with multivessel coronary artery disease as various revascularization strategies are considered.

Cardiac transplantation after bridged therapy with continuous flow left ventricular assist devices

INTRODUCTION

Cardiac transplantation is an effective surgical therapy for end-stage heart failure. Patients (pts) may need to be bridged with a continuous flow left ventricular assist device (CF-LVAD) while on the transplant list as logistic factors like organ availability are unknown. Cardiac transplantation post-LVAD can be a surgically challenging procedure and outcome in these pts is perceived to be poorer based on experience with earlier generation pulsatile flow pumps. Data from a single institution comparing these pts with those undergoing direct transplantation in the present era of continuous flow device therapy are limited.

AIM

Evaluate results of cardiac transplantation in pts bridged with a CF-LVAD (BTx) and compare outcomes with pts undergoing direct transplantation (Tx) in a single institution.

RESULTS

From June 2007 till January 2012, 106 pts underwent cardiac transplantation. Among these, 37 (35%) pts (51±11 years; 85% male) were bridged with a CF-LVAD (BTx), while 70 (65%) comprised the Tx group (53±12 years; 72% males). The median duration of LVAD support was 227 (153,327) days. During the period of LVAD support, 10/37 (27%) pts were upgraded to status 1A and all were successfully transplanted. Median hospital stay in the BTx (14 days) was slightly longer than the Tx group (12 days) but not statistically significant (p=0.21). In-hospital mortality in the BTx (5%) and Tx (1%) were comparable (p=0.25). Estimated late survival in the BTx cohort was 94±7, 90±10 and 83±16% at the end of one, two and three years, respectively which was comparable to 97±4%, 93±6% and 89±9% for the Tx group (p=0.50).

CONCLUSION

Cardiac transplantation after LVAD implant can be performed with excellent results. Patients can be supported on the left ventricular assist device even for periods close to a year with good outcome after cardiac transplantation.

Regulation of the SK3 channel by microRNA-499--potential role in atrial fibrillation

BACKGROUND

MicroRNAs are important regulators of gene expression, including those involving electrical remodeling in atrial fibrillation (AF). Recently, KCNN3, the gene that encodes the small-conductance calcium-activated potassium channel 3 (SK3), was found to be strongly associated with AF.

OBJECTIVES

To evaluate the changes in atrial myocardial microRNAs in patients with permanent AF and to determine the role of microRNA on the regulation of cardiac SK3 expression.

METHODS

Atrial tissue obtained during cardiac surgery from patients (4 sinus rhythm and 4 permanent AF) was analyzed by using microRNA arrays. Potential targets of microRNAs were predicted by using software programs. The effects of specific microRNAs on target gene expression were evaluated in HL-1 cells from a continuously proliferating mouse hyperplastic atrial cardiomyocyte cell line. Interactions between microRNAs and targets were further evaluated by using luciferase reporter assay and by using Argonaute pull-down assay.

RESULTS

Twenty-one microRNAs showed significant (>2-fold) changes in AF. MicroRNA 499 (miR-499) was upregulated by 2.33-fold (P < .01) in AF atria, whereas SK3 protein expression was downregulated by 46% (P < .05). Transfection of miR-499 mimic in HL-1 cells resulted in the downregulation of SK3 protein expression, while that of miR-499 inhibitor upregulated SK3 expression. Binding of miR-499 to the 3' untranslated region of KCNN3 was confirmed by luciferase reporter assay and by the increased presence of SK3 mRNA in Argonaute pulled-down microRNA-induced silencing complexes after transfection with miR-499.

CONCLUSION

Atrial miR-499 is significantly upregulated in AF, leading to SK3 downregulation and possibly contributing to the electrical remodeling in AF.