Mechanical Circulatory Support Devices as Destination Therapy
Mechanical Circulatory Support Devices as Destination Therapy
Many efforts have been made to optimize technical design, flow characteristics and durability of LVAD systems to enable long term support (Figure 2). A particularly important technical milestone was the implementation of the continuous flow left ventricular assist devices (CF-LVAD). In 2009, Slaughter et al. highlighted in a randomized multicentre trial with 200 DT patients, that intended treatment with CF-LVAD, in this case the Heart Mate II device, resulted in a significant better one- and two-year survival (68%, 58%) as compared to a pulsatile Heart Mate I LVAD (55%; 24%). Remarkably, 18 patients were switched from pulsatile to CF-LVAD during the follow up period. Although the functional status in both groups was improved by LVAD therapy, major adverse events, such device-related and non-device-related infections were significantly reduced in the CF-LVAD group. However, the incidence of strokes did not differ significantly between the two groups. Data from our own institution, the Heart and Diabetes Center NRW in Bad Oeynhausen, also shows better outcomes for patients treated with CF-LVADs compared to compared to the patients with biventricular pulsatile VAD's or patients on total artificial hearts (Figure 3). Furthermore, Rogers and colleagues demonstrated additional benefits for functional NYHA status and quality of life in a retrospective analysis of BTT and DT Heart Mate II patients in the above mentioned trial. In the DT (CF-LVAD) group, NYHA functional class improved from class IV to class I-II in 80% of patients at between six and 24 months. Recently, results of the post-FDA-approval study with the Heart Mate II for DT were reported. This study was a prospective evaluation of the first 247 consecutive Heart Mate II patients who underwent implantation after FDA approval of the device, and who were preoperatively identified for DT between January and September 2010. This cohort was compared to a historic patient group of DT Heart Mate II patients (n=133) of the pivotal trial. Baseline characteristics did not differ between both groups. Heart Mate II was implanted at INTERMACS levels 1 and 2 in 45% of patients, and at INTERMACS levels 2–3 in 28% of patients. Survival at one and two years was 74±3% and 61±3% in the post approval respectively, and 68±4% and 58±4% in the pivotal trial group, respectively. According to the INTERMACS levels, patient survival was worse at level 1–2 and best at INTERMACS level 4–7. Comparing adverse event rates, the authors found a general trend towards lower rates in the post approval cohort, including bleeding, device related infections, ischemic stroke and pump exchange for all reasons, but not for hemolysis, which had an increased incidence. The authors concluded that treatment with Heart Mate II for DT is superior to medical therapy in patients with terminal heart failure, but also raised a word of caution regarding the extension of LVAD implantation in 'less sick' patients, as a further reduction of adverse event rates would be essential to ultimately reach this goal. Recently, results of the investigator initiated post-market registry to evaluate the HeartWare Left Ventricular Assist System (ReVOLVE) were published. From February 2009 to December 2012, 314 HeartWare implants were enrolled into this registry. The primary outcome was defined as survival to transplant, successful recovery with the device being explanted, or ongoing continued HeartWare system support. Duration of HeartWare support ranged from 1 to 1.057 days and patient selection differed in the current study in that aspect that patients were older, and there were a higher percentage of females and patients with idiopathic cardiomyopathies compared to the ReVOLVE cohort. HTX was performed in 56 patients (22%), explant for recovery occurred in three patients (1%), 43 died whilst on support (17%), and 152 (60%) remained on the device. Successful support of patients with HeartWare was 87% at six months, 85% at one year, 79% at two years and 73% at three years. Adverse event rates were low and comparable to or even improved, compared to the CE-Mark-Trial. Complications included bleeding (28%), RV failure (9%) and driveline infections (6%).
(Enlarge Image)
Figure 2.
Patient walking his dog whilst on HeartWare support (A) and a chest X-ray of the same patient showing the position and angle of the HeartWare.
(Enlarge Image)
Figure 3.
Probability of survival for patients with different devices for DT who were treated at the Heart and Diabetes Center NRW, Bad Oeynhausen, Germany between August 2000 and March 2014 (n=160).
Outcomes of DT
Many efforts have been made to optimize technical design, flow characteristics and durability of LVAD systems to enable long term support (Figure 2). A particularly important technical milestone was the implementation of the continuous flow left ventricular assist devices (CF-LVAD). In 2009, Slaughter et al. highlighted in a randomized multicentre trial with 200 DT patients, that intended treatment with CF-LVAD, in this case the Heart Mate II device, resulted in a significant better one- and two-year survival (68%, 58%) as compared to a pulsatile Heart Mate I LVAD (55%; 24%). Remarkably, 18 patients were switched from pulsatile to CF-LVAD during the follow up period. Although the functional status in both groups was improved by LVAD therapy, major adverse events, such device-related and non-device-related infections were significantly reduced in the CF-LVAD group. However, the incidence of strokes did not differ significantly between the two groups. Data from our own institution, the Heart and Diabetes Center NRW in Bad Oeynhausen, also shows better outcomes for patients treated with CF-LVADs compared to compared to the patients with biventricular pulsatile VAD's or patients on total artificial hearts (Figure 3). Furthermore, Rogers and colleagues demonstrated additional benefits for functional NYHA status and quality of life in a retrospective analysis of BTT and DT Heart Mate II patients in the above mentioned trial. In the DT (CF-LVAD) group, NYHA functional class improved from class IV to class I-II in 80% of patients at between six and 24 months. Recently, results of the post-FDA-approval study with the Heart Mate II for DT were reported. This study was a prospective evaluation of the first 247 consecutive Heart Mate II patients who underwent implantation after FDA approval of the device, and who were preoperatively identified for DT between January and September 2010. This cohort was compared to a historic patient group of DT Heart Mate II patients (n=133) of the pivotal trial. Baseline characteristics did not differ between both groups. Heart Mate II was implanted at INTERMACS levels 1 and 2 in 45% of patients, and at INTERMACS levels 2–3 in 28% of patients. Survival at one and two years was 74±3% and 61±3% in the post approval respectively, and 68±4% and 58±4% in the pivotal trial group, respectively. According to the INTERMACS levels, patient survival was worse at level 1–2 and best at INTERMACS level 4–7. Comparing adverse event rates, the authors found a general trend towards lower rates in the post approval cohort, including bleeding, device related infections, ischemic stroke and pump exchange for all reasons, but not for hemolysis, which had an increased incidence. The authors concluded that treatment with Heart Mate II for DT is superior to medical therapy in patients with terminal heart failure, but also raised a word of caution regarding the extension of LVAD implantation in 'less sick' patients, as a further reduction of adverse event rates would be essential to ultimately reach this goal. Recently, results of the investigator initiated post-market registry to evaluate the HeartWare Left Ventricular Assist System (ReVOLVE) were published. From February 2009 to December 2012, 314 HeartWare implants were enrolled into this registry. The primary outcome was defined as survival to transplant, successful recovery with the device being explanted, or ongoing continued HeartWare system support. Duration of HeartWare support ranged from 1 to 1.057 days and patient selection differed in the current study in that aspect that patients were older, and there were a higher percentage of females and patients with idiopathic cardiomyopathies compared to the ReVOLVE cohort. HTX was performed in 56 patients (22%), explant for recovery occurred in three patients (1%), 43 died whilst on support (17%), and 152 (60%) remained on the device. Successful support of patients with HeartWare was 87% at six months, 85% at one year, 79% at two years and 73% at three years. Adverse event rates were low and comparable to or even improved, compared to the CE-Mark-Trial. Complications included bleeding (28%), RV failure (9%) and driveline infections (6%).
(Enlarge Image)
Figure 2.
Patient walking his dog whilst on HeartWare support (A) and a chest X-ray of the same patient showing the position and angle of the HeartWare.
(Enlarge Image)
Figure 3.
Probability of survival for patients with different devices for DT who were treated at the Heart and Diabetes Center NRW, Bad Oeynhausen, Germany between August 2000 and March 2014 (n=160).
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