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Clinical outcomes for continuous-flow left ventricular assist device patients stratified by pre-operative INTERMACS classification

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Background

Risk stratification for mechanical circulatory support (MCS) has emerged as an important tool in patient selection and outcomes assessment. Most studies examining risk stratification have been limited to pulsatile devices. We use the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) to stratify patients with continuous-flow devices and assess outcomes in less severe, but functionally impaired, heart failure patients.

Methods

This study included 101 bridge-to-transplant and destination-therapy patients at 3 centers. Three groups were studied: Group 1, cardiogenic shock (INTERMACS Profile 1); Group 2, inotrope-dependent (INTERMACS Profile 2 or 3); and Group 3, ambulatory advanced heart failure (INTERMACS Profiles 4 to 7). The outcomes of interest were actuarial survival, survival to discharge and length of stay.

Results

Survival at 36 months was better in Group 3 than in Group 1 (95.8% vs 51.1%, p = 0.011), but not between Groups 2 and 3 (68.8 vs 95.8%, p = 0.065). Lengths of stay for Groups 1 to 3 were 44, 41 and 17 days: Groups 1 vs 3, p < 0.001; Groups 2 vs 3, p < 0.001; and Groups 1 vs 2, p = 0.62. Lengths of stay for survivors were 49, 39 and 14 for the 3 groups: Groups 1 vs 3, p < 0.001; Groups 2 vs 3, p < 0.001; and Groups 1 vs 2, p = 0.28.

Conclusion

INTERMACS classification is a useful metric for risk-stratifying candidates for MCS. Less acutely ill but functionally impaired heart failure patients receiving continuous-flow LVADs had longer short- and long-term survival and shorter lengths of stay compared with patients who were more acutely ill.

Section snippets

Study population

Our study cohort consisted of consecutive patients implanted before August 27, 2007 at the University of Minnesota, University of Pittsburgh and Columbia University with either a VentrAssist or a HeartMate II LVAD, regardless of the original indication for implantation (BTT or DT). Each patient was categorized according to their INTERMACS classification at the time of implant by agreement between the surgeon and cardiologist at the center implanting the LVAD (Table 1), and then 3 groups were

Results

This analysis included 101 consecutive end-stage heart failure patients implanted with either a VentrAssist or a HeartMate II as BTT or DT before August 27, 2007. There were 51 patients enrolled at the University of Minnesota, 27 patients enrolled at Columbia University and 23 patients enrolled at the University of Pittsburgh. Baseline characteristics of the enrolled patients are shown in Table 2. Most of the patients enrolled were implanted as BTT. There were 28 patients in Group 1 (27.2%), 49

Discussion

Outcomes with mechanical circulatory support have gradually improved over time as a result of improvements in device technology and experience gained in intra- and peri-operative patient management. Over the past decade, there has been growing evidence regarding the importance of patient selection on outcomes with mechanical circulatory support. The pre-operative risk stratification system used in this study differs from previous models in two important ways. First, although previous

Limitations

There are several limitations to the present analysis. First, our results should be interpreted in the context of retrospective data collected across multiple sites. The overall size of the cohort was relatively small and the patients were not evenly distributed across groups, with Group 2 being nearly twice the size of the other groups. Patients were not randomized in the analysis as their groupings were based on their pre-operative classification and all patients received either a HeartMate

Disclosure statement

R.J. received a research grant from Thoratec Corporation. A.B., Y.N. and J.T. are consultants to Thoratec. The remaining authors have no conflicts of interests to disclose.

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