Total Anamolous Pulmonary Venous Return

Supracardiac (A)

R & L Pulmonary veins (PV) join in a confluence posterior to LA & are connected via ascending vertical vein to innominate vein which drains into SVC (MOST COMMON)

Infracardiac (B)

Confluence of PV drains via descending vertical vein to portal venous system to IVC

Cardiac (C)

R & L PV drain into a dilated coronary sinus or directly into RA

Mixed pattern

4 PV drain into more than one venous structure (ie. R PV to RA while L PV into vertical vein)

Pathophysiology

Obstructed Veins: Pulmonary venous hypertension is seen w/ resultant pulmonary edema.  Reflex pulm arteriolar vasoconstriction and pulm HTN are seen w/ resultant right heart failure.

Unobstructed Veins: Pulm venous return is to systemic venous circulation and blood from both venous systems is mixed. Systemic cardiac output is maintained by R à L shunt at atrial level.

Post-op complications

Low cardiac output

Previously dilated R sided structures influenced LA and LV, which made LV less compliant. LV may need high filling pressure post-operatively.

Respiratory insufficiency

Fulminant pulmonary edema prior to surgery + cardiopulmonary bypass may lead to severe respiratory compromise.

Pulmonary hypertension

Due to medial hypertrophy of pulm arterioles, pulm HTN occurs in ~50% of pts. Significant risk factor for death in immediate post-op period.

Need to rule out residual pulm venous obstruction by echo if problems post-operatively.

Arrhythmias

Usually supraventricular, occur in ~20%.

***Import to know that lowering of PA pressures and increased pulmonary blood flow post-operatively can lead to increased preload to L side of the heart leading to a bad cycle of increased LA pressure, increased PA pressure, decreased LV compliance, and increased LA pressure which all exacerbate pulm HTN!