Congenital Heart Disease in Adults

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Chapter 16 Congenital Heart Disease in Adults

Advances in perioperative care for children with congenital heart disease (CHD) over the past several decades has resulted in an ever-increasing number of these children reaching adulthood with their cardiac lesions palliated or repaired. The first paper on adult CHD was published in 1973; the field has grown such that there is now a text devoted to it, and even a specialty society dedicated to it, the International Society for Adult Congenital Cardiac Disease (http://www.isaccd.org).1 There are estimated to be about 32,000 new cases of CHD each year in the United States and 1.5 million worldwide. More than 85% of infants born with CHD are expected to grow to adulthood. It is estimated that there are more than 500,000 adults in the United States with CHD; 55% of these adults remain at moderate to high risk, and more than 115,000 have complex disease.2,3 There are as many adults with CHD as there are children, and the number of adults will only continue to increase. These patients can be seen by anesthesiologists for primary cardiac repair, repair after a prior palliation, revision of repair due to failure or lack of growth of prosthetic material, or conversion of a suboptimal repair to a more modern operation (Box 16-1). In addition, these adults with CHD will be seen for all the other ailments of aging and trauma that require surgical intervention. Although it has been suggested that teenagers and adults can have repair of congenital cardiac defects with morbidity and mortality approaching that of surgery done during childhood, these data are limited and may reflect only a relatively young and acyanotic sampling.4 Other data suggest that, in general, adults older than 50 years of age represent an excessive proportion of the early postoperative mortality encountered, and the number of previous operations and cyanosis are both risk factors. Risk factors for noncardiac surgery include heart failure, pulmonary hypertension, and cyanosis.5

These patients bring with them anatomic and physiologic complexities of which physicians accustomed to caring for adults may be unaware and medical problems associated with aging or pregnancy that might not be familiar to physicians used to caring for children. This problem has led to the establishment of the growing subspecialty of adult CHD. An informed anesthesiologist is a critical member of the team required to care optimally for these patients. A specific recommendation is that noncardiac surgery on adult patients with moderate to complex CHD be done at an adult congenital heart center (regional centers) with the consultation of an anesthesiologist experienced with adult CHD. In fact, one of the founding fathers of the subspecialty wrote: “A cardiac anesthesiologist with experience in CHD is pivotal. The cardiac anesthesiologist and the attending cardiologist are more important than the noncardiac surgeon.”2 Centers may find it helpful to delegate one attending anesthesiologist to be the liaison with the cardiology service to centralize preoperative evaluations and triage of patients to an anesthesiologist with specific expertise in managing patients with CHD, rather than random consultations with generalist anesthesiologists.

Potential Renal Implication

Potential Neurologic Implications

CARDIAC ISSUES

The basic hemodynamic effects of an anatomic cardiac lesion can be modified by time and by the superimposed effects of chronic cyanosis, pulmonary disease, or the effects of aging. Although surgical cure is the goal, true universal cure, without residua, sequelae, or complications, is uncommon on a population-wide basis. Exceptions include closure of a nonpulmonary hypertensive patent ductus arteriosus (PDA) or atrial septal defect (ASD), probably in childhood. Although there have been reports of series of surgeries on adults with CHD, the wide variety of defects and sequelae from prior surgery make generalizations difficult, if not impossible. Poor myocardial function can be inherent in the CHD but can also be affected by long-standing cyanosis or superimposed surgical injury, including inadequate intraoperative myocardial protection. This is particularly true of adults who had their cardiac repair several decades ago when myocardial protection may not have been as good and when repair was undertaken at an older age. Postoperative arrhythmias are common, particularly when surgery entailed long atrial suture lines. Thrombi can be found in these atria, precluding immediate cardioversion. Bradyarrhythmias can be secondary to surgical injury to the sinus node or conducting tissue or can be a component of the cardiac defect.

The number of cardiac lesions and subtypes, together with the large number of contemporary and obsolescent palliative and corrective surgical procedures, makes a complete discussion of all CHD impossible. The reader is referred to one of the current texts on pediatric cardiac anesthesia for more detailed descriptions of these lesions, the available surgical repairs, and the anesthetic implications during primary repair.8,9 Some general perioperative guidelines to caring for these patients are offered in Table 16-2.

Table 16-2 General Approaches to Anesthesia for Patients with Congenital Heart Disease

General
The best care for both cardiac and noncardiac surgery in adult patients with CHD is afforded in a center with a multidisciplinary team experienced in the care of adults with CHD and knowledgeable about both the anatomy and physiology of CHD and also the manifestations and considerations specific to adults with CHD.
Preoperative

Intraoperative Postoperative

Aortopulmonary Shunts

Depending on their age, adult patients may have had one or more of several aortopulmonary shunts to palliate cyanosis during childhood. These are shown in Figure 16-1. Although life saving, there were considerable shortcomings of these shunts in the long term. All were inherently inefficient, because some of the oxygenated blood returning through the pulmonary veins to the left atrium and ventricle would then return to the lungs through the shunt, thus volume loading the ventricle. It was difficult to quantify the size of the earlier shunts such as the Waterston (side-to-side ascending aorta to right pulmonary artery) and Potts (side-to-side descending aorta to left pulmonary artery). If too small, the patient was left excessively cyanotic; if too large, there was pulmonary overcirculation with the risk of developing pulmonary vascular disease. The Waterston, in fact, could on occasion result in a hyperperfused, hypertensive ipsilateral pulmonary artery and a hypoperfused contralateral pulmonary artery as it could direct flow to the ipsilateral side. There were also surgical issues when complete repair became possible. Takedown of Waterston shunts often required a pulmonary arterioplasty to correct deformity of the pulmonary artery at the site of the anastomosis, and the posteriorly located Potts anastomoses could not be taken down from a median sternotomy. Patients with a classic Blalock-Taussig shunt almost always lack palpable pulses on the side of the shunt. Even if there is a palpable pulse (from collateral flow around the shoulder), blood pressure obtained from that arm will be artifactually low. Even after a modified Blalock-Taussig shunt (using a piece of Gore-Tex tubing instead of an end-to-side anastomosis of the subclavian and pulmonary arteries), there can be a blood pressure disparity between the arms. To ensure a valid measurement, preoperative blood pressure should be measured in both arms (Table 16-3).

Table 16-3 Aortopulmonary Shunts

Waterston Ascending aorta → right pulmonary artery No longer done
Potts Descending aorta → left pulmonary artery No longer done
Classic Blalock-Taussig Subclavian artery → ipsilateral pulmonary artery No longer done
Modified Blalock-Taussig Gore-Tex tube subclavian artery → ipsilateral pulmonary artery Current
Central shunt Gore-Tex tube ascending aorta → main pulmonary artery Current