Reversal of pulmonary hypertension in paediatric patients with restrictive cardiomyopathy

Abstract

Left ventricular assist devices can reverse pulmonary hypertension in cardiac transplant candidates with heart failure with a reduced ejection fraction. Whether a similar approach is applicable in restrictive cardiomyopathy is uncertain. We report the successful implantation of a Medtronic HVAD left ventricular assist device in a bridge-to-candidacy concept in 2 paediatric patients with restrictive cardiomyopathy.

Pulmonary hypertension (PH) is frequent in patients with restrictive cardiomyopathy and a contraindication for a cardiac transplant due to the risk of post-transplant failure of the unconditioned right ventricle [1].

INTRODUCTION

Pulmonary hypertension (PH) is frequent in patients with restrictive cardiomyopathy and a contraindication for a cardiac transplant due to the risk of post-transplant failure of the unconditioned right ventricle [1].

CASE REPORT

A left ventricular assist device (LVAD) Medtronic HeartWare HVAD (Medtronic, Minneapolis, MN, USA) implant was pursued in 2 paediatric patients (patient number 1: female, 13 years of age, weight 52.6 kg; patient number 2: female, 12 years of age; weight 35.7 kg) with restrictive cardiomyopathy and PH in a bridge-to-candidacy concept. PH was considered fixed if the haemodynamic measurements could not be significantly reduced to a systemic pulmonary artery pressure <50 mmHg, a pulmonary vascular resistance <3.0 WU and a transpulmonary pressure gradient <15 mmHg after vasodynamic testing. Right heart catheterization data are seen in Table 1. In patient number 1, two-third systemic pulmonary artery pressure and only a limited response to fully exploited vasodilator treatment were revealed. Patient number 2 had suprasystemic pulmonary artery pressures, and vasoreactivity testing revealed no significant decrease.

Table 1.

Right heart catheterization data and left ventricular assist device parameters

Right heart catheterization data
Application of O2/NO	ART (mmHg) (S/D/M)	RA (mmHg) (A/V/M)	PA (mmHg) (S/D/M)	PCW (mmHg) (A/V/M)	PVR (WU)	TPG (mmHg)	CO (l/min)	CI (l/min/m2)
Patient number 1
Pre-LVAD implantation
Room air	100/58/71	5/4/4	61/31/40	27/26/26	2.4	14	5.3	3.4
O2	102/57/71	5/3/3	61/28/41	31/38/29	1.9	12	6.5	4.2
NO (10 ppm)	103/56/73	5/3/3	51/23/37	25/33/24	2.4	13	5.5	3.5
Candidacy for transplant listing
Room air	72/70/70	7/5/5	32/17/22	N.A./N.A./11	1.5	11	7	4.6
Post-transplant
Room air	94/44/61	10/3/5	32/9/18	8/13/8	1.5	10	6.9	4.5
Patient number 2
Pre-LVAD implantation
Room air	89/54/66	13/9/9	144/65/95	30/30/28	18.6	67	3.6	2.9
NO (10 ppm)	80/45/57	10/8/7	135/65/90	45/40/41	12.1	49	4	3.2
Candidacy for transplant listing
Room air	89/82/82	8/9/5	85/40/57	20/24/20	3.3	37	5.9	4.4
NO (10 ppm)	91/82/85	5/3/3	59/16/33	22/21/19	2.6	14	5.4	4.1
Post-transplant
Room air	105/49/67	5/4/1	39/6/20	6/6/4	2.8	16	4.6	3.5
Left ventricular assist device parameters
	Intraoperative LVAD parameters				One-month post-implant LVAD parameters
Patient numbers	Initial speed (rpm)	Initial flow (l/min)	Initial power (W)	Initial waveness	Speed (rpm)	Flow (l/min)	Power (W)	Waveness
Number 1	2100	4.6	2.4	3	2400	4	2.7	4
Number 2	2300	2.4	2.2	1	2600	4.1	3.5	4

ART: arterial pressure; CI: cardiac index; CO: cardiac output; LVAD: left ventricular assist device; N.A.: not available; PA: pulmonary artery pressure; PCW: pulmonary wedge pressure; PVR: pulmonary vascular resistance; RA: right atrium pressure; TPG: transpulmonary pressure gradient.

A full sternotomy was performed in both patients, and cardiopulmonary bypass was installed in the conventional fashion. An enhancement plastic procedure of the left-sided pericardium was performed with a Gore-Tex patch to secure space for the LVAD implant. In the setting of restrictive cardiomyopathy after apical coring, an additional myectomy was performed to remove obstructing parts of myocardium. Postoperative X-rays are seen in Fig. 1. The patients were discharged from the hospital 29 and 25 days after the LVAD was implanted, respectively. In addition to monitoring at the assist device outpatient clinic, a standardized telephone intervention algorithm was performed every 2 weeks. LVAD settings are seen in Table 1. PH was treated with bosentan in patient number 1 and with bosentan and sildenafil in patient number 2, respectively. Echocardiography was performed regularly to detect therapy effects early and non-invasively. If not indicated earlier, right heart catheterizations were performed every 3 months per institutional guidelines. Patients were eligible for heart transplant listing after 57 and 119 days of LVAD support. A subsequent orthotopic heart transplant was performed in both patients without any adverse events after 78 and 272 days of device support. Post-transplant catheterization revealed sustained reversal of the PH.

Figure 1:

Postoperative X-ray. (A) Postoperative X-ray (postoperative day 1) after an HVAD implant in patient number 1 with a body surface area of 1.5 m². (B) Postoperative X-ray (postoperative day 2) after an HVAD implant in patient number 2 with a body surface area of 1.2 m².

DISCUSSION

During prolonged LVAD support (88 ± 45 days) with a HeartWare HVAD, a decrease in both pulmonary artery pressure and pulmonary vascular resistance was reached. Especially children with restrictive cardiomyopathy have notably poor outcomes with a 5-year survival from the diagnosis of restrictive cardiomyopathy of 68% [2]. The condition is characterized by reduced ventricular compliance. Diastolic ventricular dysfunction leads to atrial hypertension, which results in an elevated postcapillary pressure in the pulmonary circulation [3]. The irreversibility of fixed PH is a consequence of the remodelling of the pulmonary vascular system. The use of LVADs might reverse this process by continuously unloading the left ventricle [4]. Additional extended myectomy is required in the setting of restrictive pathologies to avoid later suction events.

Funding

This study was supported by institutional grants: Edwards, Medtronic, Abbott and Berlin Heart.

Conflict of interest: none declared.

Reviewer information

Interactive CardioVascular and Thoracic Surgery thanks Christoph Schmitz and the other, anonymous reviewer(s) for their contribution to the peer review process of this article.