Biomedical subjects

Peer M Portner

Publications and source records attributed to Peer M Portner.

5 recordsLinked to original sources

PubMed2006

Relationship between renal function and left ventricular assist device use.

BACKGROUND: Poor renal function may affect outcomes after left ventricular assist device (LVAD) placement. Conversely, LVADs may optimize circulation and improve renal function. METHODS: To assess the relationship between renal function and LVAD use, changes in creatinine clearances (CrCl, in mL/min) were assessed retrospectively in 220 patients who underwent LVAD placement. These patients were also divided into four groups based on CrCl quartiles (< 47, 48-68, 69-95, and > 95) and compared for outcomes post-LVAD placement. RESULTS: Eighty-four patients died on LVAD support. Survival on LVAD was worse for patients with the worst baseline CrCl (42%, 52%, 63%, and 79% for 6 month and 26%, 34%, 47%, and 66% for 12 month survival for quartiles 1-4; both p < 0.01 for trend). Adjusting for other covariates, patients in the lowest CrCl quartile were at a higher risk of dying postimplant (odds ratio 1.95, 95% confidence interval 1.14-3.63). Paired sample analysis showed the following changes in CrCl: preoperative to week 1, 77.0 +/- 46.6 to 92.1 +/- 51.1 (p < 0.01; n = 202), week 1 to 2, 89.4 +/- 49.2 to 95.2 +/- 52.4 (p = 0.01, n = 171), week 2 to 3, 107.5 +/- 58.1 to 113.7 +/- 66.1 (p = 0.16, n = 74), and week 3 to 4, 111.1 +/- 56.6 to 110.5 +/- 56.8 (p = 0.87, n = 60). For the 60 patients with baseline CrCl less than 50, CrCl increased from 36.7 +/- 9.2 to 60.1 +/- 35.5 (p < 0.01; n = 55 pairs) from preimplant to week 1. In 37 of these patients (62%) on intraaortic balloon pump support preimplant, CrCl increased from 38.4 +/- 8.2 to 67.9 +/- 40.3 mL/minute (p < 0.01) during week 1 postimplant. Recovery of renal function to CrCl greater than 50 was associated with a trend towards better 30-day survival (84% vs 66%, p = 0.09). CONCLUSIONS: Baseline poor renal function is associated with worse outcomes after LVAD implantation. However, renal function improves substantially and rapidly in post-LVAD survivors and is associated with improved outcomes. These data underscore the importance of careful patient selection for LVAD therapy.

Adult↗

PubMed2005

Body mass index and outcomes after left ventricular assist device placement.

BACKGROUND: Although extremes of body mass index (BMI) are associated with decreased survival after cardiac transplantation, its association with outcomes after left ventricular assist device (LVAD) implantation is not known. This issue is especially important as LVADs are now approved as destination therapy for advanced heart failure patients who are not transplant candidates. In this study, we assess the association between BMI and outcomes after LVAD implantation. METHODS: A total of 222 patients who underwent LVAD placement (190 bridge-to-transplant [BTT] and 32 destination therapy) were divided into four groups based on BMI (kg/m2) quartiles (group 1, <22.9; group 2, 22.9 to 26.3; group 3, 26.4 to 29.4; and group 4, >29.4) and were compared for outcomes. RESULTS: Eighty-four patients died on LVAD support. Six- and 12-month survival on LVAD for the four groups was 35%, 60%, 65%, and 73%, and 26%, 34%, 50%, and 66% (both p < 0.01), respectively. Similar trends were seen for the composite endpoint of survival on LVAD and within 30 days posttransplant among BTT patients. Infectious, neurological, respiratory, or bleeding complications were not related to BMI. Patients with higher BMI tended to have a greater risk of reoperations (43%, 49%, 53%, and 61%, p = 0.06) and renal complications (16%, 33% 23%, 43%, p = 0.03). Age and history of thoracotomy were independently associated with mortality whereas higher BMI was not. Survival was worst for patients with lowest BMI. CONCLUSIONS: Higher BMI did not adversely affect survival after LVAD implantation and therefore relative obesity should not be considered a contraindication for LVAD placement. Further work is needed to understand and manage risks for low BMI patients.

Adult↗

PubMed2005

Diabetes and outcomes after left ventricular assist device placement.

BACKGROUND: Patients with diabetes have poorer outcomes after surgery in general. In this study, we assess the impact of diabetes on outcomes after left ventricular assist devices (LVAD) placement. METHODS AND RESULTS: Data on 222 patients (57 diabetics) who underwent Novacor LVAD placement between 1996 and 2003 were compared for outcomes among patients who did and did not have diabetes. Significant differences between the diabetics versus nondiabetics included age (56 +/- 8 versus 49 +/- 1 years, P < .01), ischemic heart failure etiology (61% versus 44%, P = .04), history of hypertension (56% versus 30%, P < .01), thoracotomy (42% versus 30%, P = .08), stroke (14% versus 5%, P = .03), and body weight (86 +/- 16 kg versus 80 +/- 17 kg, P = .03), respectively. Eighty-four patients died on LVAD support, 28 of whom were diabetic. Thirty, 180, and 365-day survival for diabetic versus nondiabetic patients was: 76.6%, 45.6%, and 30.4% for diabetics and 86.7%, 62.4%, and 47.1% for nondiabetics (P = .02 for 180 and 365-day morality). After controlling for other variables, patients with diabetes were at a higher risk of mortality (OR 1.76, 95%CI 1.05-2.94). No significant difference in survival was noted between insulin-dependent versus non-insulin-dependent diabetics. CONCLUSION: Patients with diabetes are at a higher risk of mortality after LVAD implantation.

Adult↗

PubMed2005

Insights from continued use of a Novacor Left Ventricular Assist System for a period of 6 years.

We report a patient supported with the Novacor Left Ventricular Assist System for more than 6 years and chronicle his progress as an illustration of the clinical, practical, and emotional challenges of this therapy and the benefits of an intervention that can return a morbidly ill patient to an essentially normal lifestyle. This experience underlines the importance of patient selection, optimal timing of intervention, and the potential impact of psychologic issues on outcome.

Attitude to Health↗

PubMedDate not supplied

Novacor left ventricular assist system long-term performance: comparison of clinical experience with demonstrated in vitro reliability.

Since the first implant of the Novacor wearable left ventricular assist system (LVAS) in 1993, median implant duration worldwide has increased from 93 days (max 2.2 years) to 202 days (max 4.1 years) in May 2001. In vitro reliability/durability testing of the Novacor LVAS has previously demonstrated a mean time to failure of 4.2 (3.04-5.59) years. These tests revealed a single failure mode--main bearing wear--with measurable symptoms gradually appearing before degradation of pump function. An ongoing clinical study of 37 recipients implanted for more than 1 year has shown that a simple noninvasive method of pump surveillance, derived from the in vitro experience, is well tolerated in the clinical setting. The overall clinical experience is consistent with in vitro reliability/durability tests that demonstrated 99.9%, 98.5%, and 87.4% freedom from wear at 1, 2, and 3 years (80% confidence). So far, the clinical study has shown 99.4%, 91.5%, and 91.5% freedom from wear at the same 1, 2, and 3 year intervals (95% confidence). Furthermore, the clinical findings have corroborated the in vitro experience that the wear mechanism is generally measurable and gradual, enabling elective clinical LVAS replacement or transplantation. Clinical valve performance was also monitored, using an exercise protocol and collecting comparative data on peak flows across the valves. It was determined that developing valve dysfunction could be diagnosed early and, in the failures that did occur (n = 2), these were related to the patient's disease state. In conclusion, although clinical conditions exposed the LVAS to a wide range of different environmental and hydraulic stresses, the surveillance program described appears practical and reliable, and its findings broadly parallel those of the earlier in vitro study. Additional data needed to complete formal validation continue to be collected.

Adult↗