Interventions during Cardiac Catheterization

Balloon atrial septostomy (Rashkind procedure) is performed in infants requiring communication between the pulmonary and systemic circulations for survival (e.g., transposition of the great vessels). A balloon-tipped catheter is placed across the atrial septum. The balloon is inflated to rupture the septum, thus creating an atrial septal defect and allowing shunting at the atrial level. In the case of transposition of the great vessels, oxygenated blood flowing from the lungs to the left atrium would then mix in the right atrium with venous return blood and flow into the systemic circulation through the right ventricle. Neonates presenting for this procedure are usually receiving intravenous prostaglandin E₁ to maintain a patent ductus arteriosus. It is critical that this infusion be maintained to keep the ductus patent until the atrial septostomy is complete and is determined to be of adequate size to maintain systemic oxygenation. Anesthesia for the procedure is otherwise as described earlier.

Balloon-tipped catheters have been used to dilate stenotic heart valves and great vessels. The procedure has been performed to dilate congenital pulmonary valvular stenosis,^[121] stenotic pulmonary arteries, and aortic coarctation.^[122] Balloon valvuloplasty has also been used to ameliorate acquired stenosis of the tricuspid, pulmonary, mitral, and aortic valves.^[91] The procedure is generally reserved for patients regarded as very high-risk surgical candidates. ^[123] During balloon inflation, the circulation is blocked, and severe hypotension may result that because of the tenuous condition of the patient, may not resolve immediately on deflation of the balloon. Inotropic and antiarrhythmic therapy may be necessary, and preload may need to be optimized with intravenous fluid administration. Complications of the procedure are similar to those of cardiac catheterization. In addition, valvular insufficiency may develop.

Older patients usually tolerate this procedure when local anesthetics are infiltrated at the site of catheter entry. Intravenous sedation with fentanyl, midazolam, and propofol attenuates discomfort related to the environment and balloon inflation. When the aortic valve is to be dilated, two intravenous catheters are inserted. Valvuloplasty of other valves requires only a single intravenous catheter. If the patient becomes hemodynamically unstable, the balloon must be immediately deflated. Vagal stimulation can occur with balloon inflation and may require treatment with atropine. Should major complications ensue, prompt surgical intervention may be necessary.

New developments are allowing closure of atrial septal defects with devices deployed through catheters placed across the defects in the cardiac catheterization laboratory.^[124] Secundum defects offer the best chance of successful device closure. A number of different devices are either in use or being investigated. Teams undertaking such procedures must have plans in place to deal with failure or complications resulting from the procedure. ^[125] Similarly, patent ductus arteriosus may be amenable to device closure.^[122]

A relatively new catheter-based therapeutic option is septal ablation for hypertrophic cardiomyopathy, performed in the cardiac catheterization laboratory. This technique may be performed by septal injection of ethanol or by

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