186. Case Report: Coronary Artery Bypass Grafting: An Iatrogenic Left to Right Cardiac Shunt – SUNY Downstate

CardioNerds (Amit Goyal and Daniel Ambinder) and guest host, Dr. Priya Kothapalli (UT Austin fellow and CardioNerds Ambassador), join SUNY Downstate cardiology fellows, Dr. Eric Kupferstein and Dr. Gautham Upadhya to discuss a case about a patient who had coronary artery bypass grafting that was complicated by a LIMA grafted to the great cardiac vein. Dr. Alan Feit (Professor of Medicine, SUNY Downstate) provides the E-CPR for this episode. Dr. Moritz Wyler von Ballmoos (Director, robotic cardiac and vascular surgery for Houston Methodist Cardiovascular Surgery Associates) provides a special perspective regarding coronary artery bypass grafting as it relates to this case. Episode introduction with CardioNerds Clinical Trialist Dr. Jana Lovell (Johns Hopkins).

Left Internal Mammary Artery (LIMA) to Left Anterior Descending (LAD) artery anastomosis is the cornerstone of Coronary Artery Bypass Graft (CABG) surgery. Anastomosis of the LIMA to the Great Cardiac Vein (GCV) is a known but rare complication of the surgery. Currently there are no clear guidelines in regard to further management. We report a case of a LIMA to GCV anastomosis managed with a drug eluting stent (DES) to the mid LAD after ruling out a significant left to right heart shunt.

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Case Media - Coronary Artery Bypass Grafting: An Iatrogenic Left to Right Cardiac Shunt

Angiography

Episode Schematics & Teaching - Coronary Artery Bypass Grafting: An Iatrogenic Left to Right Cardiac Shunt

Pearls - Coronary Artery Bypass Grafting: An Iatrogenic Left to Right Cardiac Shunt

Listen to the patient's story. The patient determines when the angina is no longer stable angina.The placebo effect of our interventions should not be discounted.LIMA to GCV anastomosis creates a left to right cardiac shunt. A Qp:Qs greater than 1.5 signifies a significant shunt.Increasing the pressure in the coronary sinus may actually be beneficial to the patient.LIMA-LAD is remains the most efficacious and long lasting graft but why not other arterial grafts?

Notes - Coronary Artery Bypass Grafting: An Iatrogenic Left to Right Cardiac Shunt

Iatrogenic anastomosis of the LIMA to the GCV is a rare but noted complication of CABG surgery. Review of the literature has reported under 40 such cases of arteriovenous fistula formation in the coronary system. Detection of the anastomosis generally stems from recurrent angina which can be attributed to unresolved ischemia or coronary steal syndrome but also can be detected with new heart failure (namely right sided heart failure due to left to right shunting). Diagnosis is usually made with coronary angiography, but CT coronary angiography has also been reported. Due to the rarity of this complication, no clear guidelines are in place directing the management leaving it to the discretion of the various Heart Teams. Evaluating for signs of heart failure and/or ischemia, and measuring the Qp:Qs have been the most common signs directing management. Various options are available for closing the fistula and include coil or balloon embolization, vascular plugs, venous ligation or a covered stent. Redoing the surgery is also an option. Spontaneous closure of the fistula has also been reported. Lastly, if redo surgery is not performed then regardless of fistula closure, coronary intervention for the native diseased artery may be pursued to relieve symptoms.

References

Boden et al; COURAGE Trial Research Group. Optimal medical therapy with or without PCI for stable coronary disease. N Engl J Med. 2007 Apr 12;356(15):1503-16. doi: 10.1056/NEJMoa070829. Epub 2007 Mar 26. PMID: 17387127.