A 70-year-old, highly functional female was referred to a pulmonologist for consideration of biopsy of a lung mass discovered on a chest x-ray to work up chest pain. On further detailed history, she revealed that the chest discomfort was sub-sternal and consistently happened with emotional stress or walking up hill for the last several months. She had a past history of smoking. She was not taking aspirin, nitroglycerin or beta-blockers. She was referred for a stress echo for further evaluation.
On echocardiography, at rest her LV function was normal without any regional wall motion abnormalities or significant valve disease. During the exercise stress test, she developed chest pain at three minutes of the Bruce protocol. The test had to be terminated at six minutes because of continued chest pain, which resolved quickly in recovery. EKG showed 2 mm inferolateral ST depression during exercise. Immediately post stress echocardiography showed akinesis of the distal anterior wall, apex and distal anterior septum. The posterior and lateral wall became hypokinetic. The inferior wall augmented normally with exercise. Compared with rest images, the LV cavity was noted to dilate post stress (Video Clip 1 and Video Clip 2).
Given these findings, the patient was immediately seen by a cardiologist who initiated aspirin and referred her for cardiac catheterization. Cardiac catheterization revealed a 99% proximal left main coronary artery lesion with no significant obstruction in the distal left vessels. The right coronary artery had no significant obstruction (Video Clip 3 and Video Clip 4).
What should be the next step in the management of this patient?
The correct answer is: 1. Admit, revascularize with CABG
Isolated left main stenosis is found in ~ 5% of patients undergoing cardiac catheterization. Medically treated patients with left main stenosis have a three-year mortality of 50-60%.1,2 In lieu of the high-risk features of the stress test and the critical left main lesion, the patient was admitted for IV heparin therapy. According to the appropriate use criteria, in patients with isolated left main stenosis, CABG is a reasonable option for revascularization. The role of PCI in isolated unprotected left main stenosis is considered uncertain.3 While meta-analyses of single center studies suggest favorable results after PCI with drug eluting stents (DES), currently there are no large conclusive head to head comparisons of the two revascularization approaches.4 A large multicenter trial, EXCEL, which will randomize patients to either receive PCI with DES or CABG for an isolated left main stenosis is currently under way and results will hopefully provide guidance in situations of clinical equipoise. (http://clinicaltrials.gov/show/NCT01205776). However, in this patient, with a high likelihood of the need for surgical procedures within the near future, commitment to the use of an antiplatelet agent for a year would have been unsuitable.
A chest CT scan revealed a 3 x 3 x 3 cm spiculated right upper lobe mass causing obstruction to right upper lobe airways. PET revealed a hypermetabolic focus in the same region concerning for malignancy. Axillary adenopathy was also noted.
After an interdisciplinary conference and discussion with the patient, a CABG was undertaken with intraoperative biopsy of the lung mass and axillary lymph node. The patient had an uneventful recovery. Pathology of the lymph node revealed low-grade follicular lymphoma and the lung mass was found to be non-small cell lung cancer without clear regional spread. According to the TNM staging system, the patient has a predicted five-year survival of < 50%. The patient is now slated to undergo lobectomy followed by chemotherapy for lung cancer.
While there is no clear correct answer to this difficult clinical scenario, the approach in this patient was mainly guided by the most pressing symptoms and problem. The AUC document facilitates revascularization decisions but provides guidance only in a limited number of clinical scenarios. With an aging population and rising co-morbidities, medical decision-making is becoming increasingly complex. Future guideline documents and expert consensus statements will likely need to bridge subspecialties in medicine and evaluate competing risks for death.
Taylor HA, Deumite NJ, Chaitman BR, Davis KB, Killip T, Rogers WJ. Asymptomatic left main coronary artery disease in the coronary artery surgery study (cass) registry. Circulation 1989;79:1171-1179.
Patel MR, Dehmer GJ, Hirshfeld JW, Smith PK, Spertus JA. ACCF/SCAI/STS/AATS/AHA/ASNC/HFSA/SCCT 2012 appropriate use criteria for coronary revascularization focused update J Am Coll Cardiol 2012;59:857-881.
Fajadet J, Chieffo A. Current management of left main coronary artery disease. Eur Heart J 2012;33:36-50b.