Objective
Develop a novel approach of optimizing continuous flow left ventricular assist device (CF-LVAD) function and diagnosing device malfunctions.
Background
In CF-LVAD patients, the dynamic interaction of device speed, left and right ventricular decompression, and valve function can be assessed during an echocardiography-monitored speed ramp-test.
Methods
We devised a unique ramp-test protocol to be routinely done at the time of discharge for speed optimization and/or if device malfunction was suspected. The patient’s left ventricular end diastolic dimension (LVEDD), frequency of aortic valve (AV) opening, valvular insufficiency, blood pressure, and CF-LVAD parameters were recorded at increments of 400 rpm from 8,000 rpm to 12,000 rpm. The results of the speed designations were plotted, and linear function slopes for LVEDD, PI, and power were calculated.
Results
Fifty-two ramp-tests from 39 patients were prospectively collected and analyzed. Twenty-eight ramp-tests were performed for speed optimization, and speed was changed in 17 (61%) with a mean absolute value adjustment of 424±211 rpm. Seventeen patients had ramp-tests performed for suspected device thrombosis and 10 tests were suspicious for device thrombosis; these patients were then treated with intensified anticoagulation and/or device exchange/emergent transplant. Device thrombosis was confirmed in 8/10 cases at the time of emergent device exchange or transplant. All patients with device thrombosis, but none of the remaining patients, had a LVEDD slope > −0.16.
Conclusion
Ramp-tests facilitated optimal speed changes and device malfunction detection, and may be used to monitor the effects of therapeutic interventions and need for surgical intervention in CF-LVAD patients.
Background-Aortic insufficiency (AI) is increasingly recognized as a complication of continuous flow left ventricularassist device support; however, its long-term prevalence, clinical significance, and efficacy of potential interventions are not well known. Methods and Results-We studied the prevalence and management of AI in 232 patients with continuous flow left ventricular assist device at our institution. Patients with aortic valve (AV) surgery before left ventricular assist device implantation were excluded from analysis. To examine the prevalence of de novo AI, patients without preoperative AI were divided into a retrospective and a prospective cohort based on whether a dedicated speed optimization study had been performed at the time of discharge. Forty-three patients underwent AV repair at the time of implant, and 3 subsequently developed greater than mild AI. In patients without surgical AV manipulation and no AI at the time of implant, Kaplan-Meier analysis revealed that freedom from greater than mild de novo AI at 1 year was 77.6±4.2%, and that at least moderate AI is expected to develop in 37.6±13.3% after 3 years. Nonopening of the AV was strongly associated with de novo AI development in patients without prospective discharge speed optimization. Seven of 21 patients with at least moderate AI developed symptomatic heart failure requiring surgical intervention. Conclusions-AI is common in patients with continuous flow left ventricular assist devices and may lead to clinical decompensation requiring surgical correction. The prevalence of AI is substantially less in patients whose AV opens, and optimized loading conditions may reduce AI prevalence in those patients in whom AV opening cannot be achieved.(Circ Heart Fail. 2014;7:310-319.)
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