John W. Moore, MD. Robert L. Spicer, MD. James W. Mathewson, MD. William C. Kirby, MD. This report describes 2 patients with hypoplastic left heart syndrome ...
Case
Reports
High-Risk
Angioplasty
Coarctation of the Aorta after Norwood Stage 1 John W. Moore, MD Robert L. Spicer, MD James W. Mathewson, MD William C. Kirby, MD
This report describes 2 patients with hypoplastic left heart syndrome who developed severe coarctations of the aorta after Norwood Stage I procedures and subsequently survived recurrent ventricular fibrillation during successful percutaneous angioplasty. Although ventricular fibrillation has not been associated with hypoplastic left heart syndrome, postoperative Norwood Stage I, or angioplasty of isolated coarctations of the aorta, we believe that the complex physiology of our patients created conditions that precipitated ventricular tachycardia and ventricular fibrillation. We strongly recommend that follow-up of infants with hypoplastic left heart syndrome after Norwood Stage I operations be meticulous; that even mild coarctation be treated aggressively, to avoid progression to high-risk situations; and that interventionalists be prepared to manage malignant ventricular dysrhythmias whenever postoperative Norwood Stage I patients undergo percutaneous angioplasty for coarctation of the aorta. (Texas Heart Institute Journal 1993;20:48-50)
.erctalneotis lballofon angioplasty is recognizecd as safe and effective treatfor isolatecd native and restenotic coarctation of the aorta. Coarctation of the aorta also can develop in patients w!ith hypoplastic left heart syndrome after the Norwood Stage I procedure;- and this condition, too, is amenable to balloon dilation.' This report describes 2 patients wvith hypoplastic left heart syndrome who developecl severe coarctations after Norwood Stage I procecutres. They sUrvived recuLrrent ventricular fibrillation duLring suLccessful percutat.neous angioplasty. The uLniqLue factors contrihuting to mialignant cardiac dysrhythmias in these patients are CliscuLssed. P
ment
Patient 1 founcd to have hypoplastic left heart syncdrome at 2 babY boy of age, and underwent NorwvN'ood Stage I procecdLure at 1 week. At 4 montls, he was failing to thrive and displayed cardiomegalv, upper extreimiity lhypertension, and absent femiioral puLlses. Noninvasive evaluation demonstrated a severe coarctation of the aorta, right ventricular dysfunction, and 3+ tricuLspid regurgita-
A 3-kg term
was
days
Key words: Angioplasty, balloon; aortic coarctation; hypoplastic left heart syndrome; Norwood procedure; ventricular fibrillation From: The Division of Pediatric Cardiology, Children's Hospital-San Diego, California (Drs. Moore, Spicer, and Mathewson); and the Division of Pediatric Cardiology, Walter Reed Army Medical Center, Washington, DC (Dr. Kirby)
Address for reprints: John W Moore, MD, Children's Associated Medical Group, Division of Cardiology, 8001 Frost Street, San Diego, CA 92123 48
tion. When cardiac catheterization
was performecl, pressuLres in the ascending aorta ancl descending thoracic aorta were I10/40 mmilHg (imiean, 68 mmHg) and 60/44 1 10 mmllHg, mimiHg (mean, 52 mmHg), respectively. Right ventricular pressuLre 690(o. wvith an end-diastolic pressuLre of 10 mimlHg. Room-air oxygen saturation An angiogram confirmiied a severe coarct.ation of the alorta (Fig. 1), and decision wvas made to perfoi-irm angioplastv. A P)ulse D catheter (LJSCI; TewksbLiy, Massaclhlusetts, USA) with an 83-mm btalloon (diameter at fuLll inflation) was passed over a gulidewire, throughl the femoral vein and the right heart, then positionecl in the clescending thoracic aorta distal to the coarctation. When a test inflation was performecl at 2 atmosplheres of presSLure (full inflation) for a dluration of 5 seconcs, the patient developed XventricuLlar fibrillation after a slhort run of ventriculaIr tachyrcardia (Fig 2). FullI resuLscitation enSLecl, incluiding external coimpressions. intuLbXation and ventilation, administration of sodiuLimi bicarbonate ancd Ringer's lactate, and defilbrillation. DUring resuscitation, the angioplasty balloon was repositionecl and the coarctated segment wAas dilated. Cardiac rhythm remained unstable, and the patient reentered ventriculalr fihrillation 2 additional times. Each time, wve defibrillated him, adiministered lidocaine and bretvliunv and performedt transvenous atrial pacing. Subsequently. the patient's condition stabilized, and there were no fuLrther cardiac dvsrhvthmias. After lhemiodynamic stability had been achieved, echo cardiography
Angioplasty after Norwood Stage
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Fig. 1 Lateral cineangiogram, showing severe coarctation of the aorta prior to angioplasty (patient 1).
F..al Artery
50 mm Hq
echocardiography. She underwent a Norwood Stage I procedure at 1 week of age. At 3 months of age, she was noted to have cardiomegaly and progressive development of peripheral edema. Echocardiography demonstrated a severe coarctation of the aorta at the site of the distal anastomosis, poor right ventricular function, and 4+ tricuspid regurgitation. Upon cardiac catheterization, pressures in the ascending aorta and descending thoracic aorta were 140/40 mmHg (mean, 70 mmHg) and 60/40 mmHg (mean, 51 mmHg), respectively. Right ventricular pressure was 140/12 mmHg. Room-air oxygen saturation was 78%. Angioplasty was performed with a Proflex 5 catheter (PSG; Mountain View, California, USA) placed retrograde via the femoral artery, then guided over a wire positioned in the ascending aorta. This catheter is equipped with a 6-mm balloon (diameter at full inflation). During angioplasty, the patient's cardiac rhythm and oxygen saturation level remained stable. While the catheter was being removed, the patient's rhythm abruptly changed to ventricular fibrillation after a short run of ventricular tachycardia (Fig. 3). The patient was defibrillated with 10 wattseconds of energy, and lidocaine was administered. A hemodynamic catheter was placed after the angioplasty catheter had been removed. Pressure distal to the dilated area was 108/46 mmHg (mean, 70), while proximal pressure (in the right arm) was 110/ 47 mmHg (mean, 72 mmHg). During the next 3 hours, the patient had recurrent episodes of ventricular fibrillation between intervals (ranging from 1 to 5 minutes in duration) of hemodynamic and electrical stability. Each episode required electrical defibrilla-
1 1 1 1 1111111 1 1 1 1 1 1 1 1 IIIlullll4lllllllqlllIIIIIIIIIIIIIIBI IIIIIIIIIIIBI IIIII(I 1II1
11111111111 111111j11111^11 .IIIIIDIIIIIIDIIIIIIIJI^II*I;III^D*III Illlllllllll Fig. 2 Rhythm strip and distal aortic pressure tracing, showing abrupt onset (during sinus rhythm and with an adequate aortic pressure) of ventricular tachycardia, and its degeneration into ventricular fibrillation (patient 1).
Femora Artery
i 1 1 1 1 \ f \J \ T X
So~~~~~5 mm Hq
demonstrated no pericardial effusion and no residual gradient. Furthermore, blood pressure readings in the right arm and the right leg were equal (110/90 mmHg). Room-air oxygen saturation was 70%.
Patient 2 A 2.8-kg term baby girl had been found, upon fetal echocardiography, to have hypoplastic left heart syndrome, a diagnosis that was confirmed by postnatal Texas Hean Institutejourtial
Fig. 3 Rhythm strip and distal aortic pressure tracing, showing abrupt onset (during sinus rhythm and with an adequate aortic pressure) of ventricular tachycardia, and its degeneration into ventricular fibrillation (patient 2).
Angioplasty after Norwood Stage
49
tion. There were 70 such episodes, and the closage required for each defibrillation increasecl fromii 10 to 50 watt-seconds dluring the course of resuscitation. Furthermore, the patient was treated with continuous lidocaine infusion, bretylium, atrial pacing, and a loading dose of procainamilde. Arterial blood gases during this period were obtained serially and showed no acidosis. Cheimiical stucdies of the serum revealed no significant abnormalities of electrolyte, calcium, or magnesium levels. Furtlherimiore, there was no catheter in the patient's right ventricle or near the aortic root, and echocardiography demonstrated no pericardial effusion. After the patient's cardiac rhythm andl hemodynamics stabilized, she was taken to the intensive care unit, where she was weanecl gradually from antidysrhythmic medicines over several days, without further episodes of ventricular fibrillation. Her roomair oxygen saturation was 75% after stabilization.
Discussion Outside the immediate setting of open-heart surgery, ventricular fibrillation is rare in children. In children who clie as a consequence of cardiac electrical events, only 6% have ventricular fibrillation, while the rest have bradycardia and asystole. Ventricular fibrillation, when it occurs, has been associated with Wolff-Parkinson-White syndrome, long QT syndrome, myocarditis, hypertrophic cardiomyyopathy, and extreme ventricular hypertrophy. Ventricular fibrillation has not been associated with hypoplastic left heart syndrome, postoperative Norwood Stage I, or angioplasty of isolated coarctations of the aorta.; Certainly, the physiology of severe coarctation of the aorta in association with hypoplastic left heart syndrome, postoperative Norwood Stage I, is unique. As in isolated coarctations, there is proximal compartment hypertension and high systemic vascular resistance. This results in cardiac hypertrophy and may cause, as in our patients, significant myocardial dysfunction or failure. In addition, the systemic-topulmonary-artery shunt provides a relatively low resistance reservoir connected to the proximal compartment, creating the potential for coronary steal and ischemia. Angioplasty further complicates the physiologic process, initially by increasing systemic resistance even more, and subsequently by lowering systemic resistance precipitously. Both changes have the potential to destabilize the cardiac rhythm through creation of acidosis and myocardial oxygen supply-demandc mismatch. Moreover, after angioplasty, a heightenecl potential for coronary steal and further ischemia exists because of creation of a 2nd, competing low-resistance reservoir in the distal systemic compartment. We believe that severe hypertrophy, failing myocardium, ischemia caused by 50
Angioplasty after Norwood Stage
th e coronary steal phenomenon, and possibly acidosis wer-e the factors precipitating ventricular tachycardia and ventricular fibrillation in our patients. There is 1 previously published report of a small number of patients who had angioplasty for coarctation after Norwood Stage I operations. These patients had intraoperative angioplasty and, therefore, may have had a better controlled physiologic environment. Furthermore, the clinical data suggest that these coarctations were less severe than those observed in our patients (average gradient of 45 mmHg, vs 65 mmHg in our patients). Dysrhythmias were not reported during these procedures.' However, subsequent to publication of the series, the author encountered problems with ventricular fibrillation and cardiac arrest in other patients undergoing percutaneous angioplasty of severe coarctation associated with hypoplastic left heart syndrome after Norwood Stage I.* Our experience with these cases has heightened our alertness to the follow-up of infants with hypoplastic left heart syndrome after Norwood Stage I operations. We believe that even mild coarctation, when in evidence, should be treated aggressively in order to avoid progression to the high-risk situations encountered in our patients. On the basis of known characteristics of healing and scar formation, we believe a safe interval between surgery and angioplasty shcouldl be about 10 weeks. Furthermore, because of the complex physiology of the postoperative Norwood Stage I patient, we strongly recommend that the interventionalist be prepared to manage malignant ventricular dysrhythmias whenever such patients undergo percutaneous angioplasty for coarctation of the aorta.
References 1. lTynan M, Finley JP, Fontes V, Hess J, Kan J. Balloon angioplasty for the treatment of native coarctation: results of valvulloplasty and angioplasty of congenital anomalies registry. Am J Cardiol 1990;65:790-2. 2. Hellenhrand WE, Allen HI), Golinko Ri, Hagler 1)J, Lutin W, Kan J. Balloon angioplasty for aortic recoarctation: results of valvuloplasty and angioplasty of congenital anomalies registry. Am J Cardiol 1990;65:793-7. 3. Jonas RA, Lang P, Hansen D, Hickey 1', Castaneda AR. Firststage palliation of hypoplastic left heart syndrome: the importance of coarctaltion ancl shunt size. J Thorac Cardiovasc
Surg 1986;92:6-13. 4. MuLrphy JD, Sands BL, Nor'vood WI. Intraoperative balloon angioplasty of aortic coarctation in infants with hypoplastic left heart syndromiie. Am J Cardiol 1987;59:949 -51. 5. Garson AJr. Ventricular arrhythmias. In: Garson AJr, Bricker 11, McNamara DG, eds. The science and practice of pediatric cardiology. Vol 3. Philadelphia: Lea & Fehiger, 1990;
1864-904.
*Murphy JD. P'ersonal Comlllulnication, May 1992. Volione 20, Number 1, 199.3
