Effects of Acute Pump Speed Changes on Cerebral Hemodynamics in Patients With an Implantable Continuous-Flow Left Ventricular Assist Devices.

Mechanical circulatory support (MCS) with an implantable left ventricular assist device (LVAD) is an established therapeutic option for advanced heart failure. Most of the currently used LVADs generate a continuous stream of blood that decreases arterial pulse pressure. This study investigated whether a change of the pulse pressure during different pump speed settings would affect cerebral autoregulation and thereby affect cerebral blood flow (CBF). The study included 21 haemodynamically stable outpatients with a continuous-flow LVAD (HeartMate II, Abbott, USA) implanted a median of 6 months before the study (interquartile range 3 to 14 months). Arterial blood pressure (measured by finger plethysmography) was recorded simultaneously with CBF (measured by transcranial Doppler ultrasound) during baseline pump speed (8900 rpm [IQR 8800; 9200]) and during minimum and maximum tolerated pump speeds (8000 rpm [IQR 8000; 8200] and 9800 rpm [IQR 9800; 10 000]). An increase in LVAD pump speed by 800 rpm [IQR 800; 1000] from the baseline lead to a significant decrease in arterial pulse pressure and cerebral blood flow pulsatility (relative change ?24% and ?32%, both p < 0.01), but it did not affect mean arterial pressure and mean CBF velocity (relative change 1% and ?1.7%, p = 0.1 and 0.7). In stable patients with a continuous-flow LVAD, changes of pump speed settings within a clinically used range did not impair static cerebral autoregulation and cerebral blood flow.

Endothelial dysfunction expressed as endothelial microparticles in patients with end-stage heart failure.

Left ventricular assist devices (LVAD), currently used in treatment of terminal heart failure, are working on principle of rotary pump, which generates continuous blood flow. Non-pulsatile flow is supposed to expose endothelial cells to high stress and potential damage. Therefore, we investigated longitudinal changes in concentration of circulating endothelial microparticles (EMP) as a possible marker of endothelial damage before and after implantation of LVAD. Study population comprised 30 patients with end-stage heart failure indicated for implantation of the Heart Mate II LVAD. Concentrations of microparticles were measured as nanomoles per liter relative to phosphatidylserine before and 3 months after implantation. At 3 months after implantation we observed significant decrease in concentration of EMP [5.89 (95 % CI 4.31-8.03) vs. 3.69 (95 % CI 2.70-5.03), p=0.03] in the whole group; there was no difference observed between patients with ischemic etiology of heart failure (n=18) and with heart failure of non-ischemic etiology (n=12). In addition, heart failure etiology had no effect on the rate of EMP concentration decrease with time. These results indicate possibility that LVAD do not cause vascular damage 3 months after implantation. Whether these results suggest improvement of vascular wall function and of endothelium is to be proved in long-term studies.

Biventricular pacing in the early postoperative period after cardiac surgery.

Cardiac resynchronization therapy is not commonly used in the early postoperative period in patients undergoing cardiac surgery who have left ventricular (LV) dysfunction and a history of heart failure. We performed a prospective randomized clinical trial to compare atrial synchronous right ventricular (DDD RV) and biventricular (DDD BIV) pacing within 72 hours after cardiac surgery in patients with an EF ≤35 %, a QRS interval longer than 120 msec and who had LV dyssynchrony detected by real-time three-dimensional echocardiography (RT3DE). Epicardial pacing was provided by a modified Medtronic INSYNC III pacemaker. An LV epicardial pacing lead was implanted on the latest activated segment of the LV based on RT3DE. The study included 18 patients with ischemic heart disease, with or without valvular heart disease (14 men, 4 women, average age 71 years). Patients undergoing DDD BIV pacing had a statistically significant greater CO and CI (CO 6.7±1.8 l/min, CI 3.4±0.7 l/min/m(2)) than patients undergoing DDD RV pacing (CO 5.5±1.4 l/min, CI 2.8±0.7 l/min/m(2)), p<0.001. DDD BIV pacing in the early postoperative period after cardiac surgery corrects LV dyssynchrony and has better hemodynamic results than DDD RV pacing.

Is severe pulmonary hypertension a contraindication for orthotopic heart transplantation? Not any more.

Pulmonary hypertension (PH) unresponsive to pharmacological intervention is considered a contraindication for orthotopic heart transplantation (OHTX) due to risk of postoperative right-heart failure. In this prospective study, we describe our experience with a treatment strategy of improving severe PH in heart transplant candidates by means of ventricular assist device (VAD) implantation and subsequent OHTX. In 11 heart transplantation candidates with severe PH unresponsive to pharmacological intervention we implanted VAD with the aim of achieving PH to values acceptable for OHTX. In all patients we observed significant drop in pulmonary pressures, PVR and TPG (p < 0.001 for all) 3 months after VAD implantation to values sufficient to allow OHTX. Seven patients underwent transplantation (mean duration of support 216 days) while none of patients suffered right-side heart failure in postoperative period. Two patients died after transplantation and five patients are living in very good condition with a mean duration of 286 days after OHTX. In our opinion, severe PH is not a contraindication for orthotopic heart transplantation any more.

[Technique of implantation and experience with temporary mechanical cardiac support in right ventricular failure]. / Technika implantace a zkusenosti s docasnou mechanickou srdecní podporou pri selhání pravé komory.

AIM: Severe right heart failure remains unfrequent but fatal complication of cardiac surgical procedures. Implantation of temporary right ventricular assist device may be life-saving procedure in various situations of right heart failure as: heart transplantation, LVAD therapy and post-cardiotomy failure. The aim of the study is an introduction of the implantation technique and retrospective review of current experience with the method. MATERIAL AND METHODS: Since January 2007 isolated right ventricular assist device Levitronix CentriMag has been implanted in 16 patients. Patients were divided into 3 groups: post transplantation (post-Tx), post LVAD implantation (post-LVAD) and other cardiac procedures (OCP). Success rate of weaning from RVAD, 30-days mortality and major complications has been assessed. OUTCOMES: Distribution of implants in groups was: post-Tx 5 pts (31%), post-LVAD 6 pts (38%) and 5 in OCP group (31%). The mean support time was 12 days. Off-pump implantation was achieved in 9 pts. The device was successfully weaned in 13 (81%) patients. 30-days mortality occurred in 1 case only. CONCLUSION: Presented outcomes are encouraging for broader acceptance of the therapy. Excellent success rate has been reached in post-Tx and post-LVAD. This study emphasises decesive role of proactive approach in early indication of RVAD implantation for achieving satisfactory results.

[Right ventricular dysfunction after left ventricular assist device implantation]. / Dysfunkce pravé komory po implantaci levostranné mechanické srdecní podpory.

OBJECTIVE: The frequency of long-term left ventricular assist device (LVAD) implantation is increasing. Acute right ventricular dysfunction or right ventricular failure after LVAD implantation has important influence on morbidity and mortality. The aim of our study was to assess the management of right ventricular dysfunction after LVAD implantation. METHODS: The study group comprised 21 patients with implanted HeartMate II LVAD since December, 2006 to April, 2009. We evaluated in retrospective fashion baseline parameters of cardiovascular and other organ systems before LVAD implantation, applied pharmacological and mechanical support for the right ventricle, and important clinical outcomes to the end ofJune, 2009. RESULTS: LVAD was implanted in 18 men and 3 women with mean age of 48.7 +/- 11.2 years. The most frequent diagnosis was dilatational cardiomyopathy (9 patients; 42.9%), and the most frequent indication for implantation was bridge-to-transplantation (19 patients; 90.4%). Pharmacological support of the right ventricle after LVAD implantation comprised dobutamine (21 patients; 100%), milrinone (21 patients; 100%), isoproterenol (1 patient; 4.8%), and levosimendan (5 patients; 23.8%). In 2 (9.5%) cases there was a need for repeated application of levosimendan during postoperative course. Inhalational nitric oxide was used in 14 (66.7%) patients. Despite extensive pharmacological support, 3 (14.3%) patients needed right ventricular assist device (RVAD) implantation. Most patients (9; 42.8%) survived to heart transplantation; in one (4.8%) case LVAD was successfuly explanted; 6 (28.6%) patients is living with LVAD; 5 (23.8%) patients died during LVAD support. CONCLUSION: After LVAD implantation there is a need for aggressive pharmacological, and in some cases mechanical, support of the right ventricular function to provide adequate blood flow to LVAD in order to minimize morbidity and mortality.

Does angiotensin-converting enzyme polymorphism influence the clinical manifestation and progression of heart failure in patients with dilated cardiomyopathy?

To evaluate the role of angiotensin-converting enzyme (ACE) polymorphism on the development of end-stage dilated cardiomyopathy, the ACE gene polymorphism of 90 patients after heart transplantation because of this disease was compared with the population sample. No difference in gene frequencies was found, but when compared with the population sample there were fewer ID heterozygotes detected; no significant influence of ACE polymorphism on the course of the disease before transplantation was found.