We read with great interest the article published in Revista Española de Cardiología by Varela-Falcón et al.1 about their experience of a left ventricular assist device (LVAD) in a patient with hypertrophic cardiomyopathy. We would like to raise a number of points for consideration in relation to this article.
First, we would like to congratulate the authors for the good outcome in this case, given the challenge it presented. In the last decade, LVADs have become a standard treatment option for improving survival and quality of life in patients with dilated cardiomyopathy and advanced heart failure, whether as a bridge to transplant or as a destination therapy2; however, there is little experience of this therapy in patients with cardiomyopathy and restrictive physiology, and it is not without complications.3
The article described a patient with hypertrophic obstructive cardiomyopathy in an advanced stage of heart failure, but did not provide details on the patient's left ventricular function before implantation. Nor did it explain why surgical myectomy was not performed, given the high dynamic left ventricular outflow tract gradient that was reported. An improvement in this gradient could have reduced the wedge pressures and improved the transpulmonary gradient.
One of the main complications during follow-up of patients with cardiomyopathy associated with apical hypertrabeculation are suction events and the increased incidence of thrombotic and embolic events. The authors state that in this case they decided not to perform surgical resection of the trabeculae due to the risk of incomplete resection. However, in our experience, incomplete resection of apical trabeculae increases the likelihood of suction events and thrombosis, particularly in hypertrabeculated ventricles, and careful examination of the ventricular cavity is recommended, putting the patient on bypass if necessary.4
We would also like to comment on the difficulty of inotropic treatment when initiating LVAD support and in the immediate postoperative period in these cases. In most centers, the usual practice during LVAD implantation is vasoactive support with adrenaline and milrinone to reduce the probability of right heart failure, as the authors mention. However, in this case, by not performing a myectomy despite the dynamic left ventricular outflow gradient, they may have created the ideal environment for suction events. The vasoactive support could have increased the left ventricular outflow tract gradient and also created a high intraventricular gradient due to the increased midventricular inotropy facilitated by the adrenaline, together with the suction created by the LVAD. Considering these factors, despite the good outcome described, we believe that the performance of myectomy during implantation could help to improve the postoperative treatment of patients with obstructive left ventricular outflow tract gradients.
We would like to add that long-term ventricular assistance in cardiomyopathies with restrictive physiology is a challenge. The most important determining factor when considering LVAD implantation in these patients is probably the dimensions of the cardiac chambers. Grupper et al.3 reported the largest published series of patients with cardiomyopathy, restrictive physiology, and LVADs, and observed that patients with smaller ventricles had a worse prognosis. In such patients, it is generally very difficult to achieve adequate ventricular assistance because they are very sensitive to volumetric changes and they are prone to suction events with postural changes. This often means that the revolutions of the device have to be reduced to avoid the cavity collapsing, and this, in turn, increases the risk of pump thrombosis and/or embolic events. Therefore, careful anticoagulant and antiplatelet therapy is required in these patients.
Last, we would like to congratulate the authors once more on the good outcome they achieved, although in our opinion LVAD therapy in cardiomyopathy with restrictive physiology is not free from significant complications and should be reserved for centers with a high annual caseload.