Transcatheter closure of CAF is feasible and should be considered in carefully selected patients. Recanalization of the treated coronary fistulae can occur, so follow-up angiography or other imaging modality should be performed in these patients.

Over the years there has been considerable improvement in the clinical outcomes of patients treated for acute coronary syndrome (ACS). Despite a significant reduction in acute mortality, a large percentage of patients post ACS continue to experience adverse cardiovascular (CV) events, with high long-term mortality rates and overall suboptimal medical management. Long-term risk prediction tools rely on traditional CV risk factors and are developed and validated in specific populations. Established CV risk factors, however, only explain half or fewer of CV events. These risk models may thus not be optimal in determining individual risk for long-term adverse outcomes or in helping to identify individual patients who do not respond to therapy. Identifying the specific plaque characteristics associated with increased likelihood for thrombotic complications and rapid progression has led to the concept of the vulnerable plaque. Recently, “vulnerable myocardium” (ie, myocardium that is prone to myocardial ischemia and fatal arrhythmia) has been shown to play an important role in outcome. Both vulnerable plaque and vulnerable myocardium are associated with functional vascular abnormalities, such as endothelial dysfunction, which are considered a key event in the initiation, progression and complications of coronary artery disease. Endothelial dysfunction may serve as an underlying unifying mechanism that would independently predict long-term outcome in patients with ACS undergoing revascularization.

Objectives We set to measure the inter-atrial pressure gradient during simulated obstructive sleep apnea (OSA). Background OSA occurs when a sleeping patient attempts to inhale against an obstructed airway. How this event affects the inter-atrial pressure gradient has not been defined. We hypothesized that simulated OSA in a conscious subject (Mueller maneuver [MM], inspiration against obstruction) would promote increased right-to-left pressure gradient, and then the substrate for right-to-left atrial shunting. Methods Selected patients underwent simultaneous measurement of airway and atrial pressures (both left and right atrium [LA, RA]) using high-fidelity micromanometry at rest, during MM, and during VM, during right heart catheterization. Results Ten patients (age 55±11 years, 2 women) were successfully studied. During the onset of MM, RA pressure transiently but consistently exceeded LA pressure in response to the steep decline in intra-thoracic pressure (maximum RA-LA pressure gradient increased from 0.1±1.4 mmHg at baseline to 7.0±4.3 mmHg during MM, p<0.001). The maximum right-to-left atrial pressure gradient during Mueller maneuver was higher than that achieved during the Valsalva maneuver release (p<0.007). Conclusions The onset of MM increased right-to-left pressure gradient across the atrial septum, likely as a result of greater blood return to the RA from extra-thoracic veins. The RA-LA pressure gradient achieved during MM was greater than that observed during VM. These findings delineate the hemodynamic substrate for right to left shunting during OSA.

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