Percutaneous intervention of left main coronary artery disease: a fresh look at a class III recommendation.

To the Editor: Percutaneous intervention of left main coronary artery (LMCA) disease is a class III recommendation per the latest guidelines published by the American Heart Association/American College of Cardiology. (1) As techniques, technologies, research, and pharmaceuticals advance, intervention on LMCA disease has become a more feasible option. We present two cases, both with different indications, but sharing a common conclusion.

Case 1 was a 57-year-old white male with a history of severe chronic obstructive pulmonary disease who was transferred to our institution with acute coronary syndrome, having AV dissociation with widened QRS complexes and elevated cardiac enzymes. Echocardiography demonstrated a large anteroapical infarct noted by akinetic anteroseptal and anterior walls as well as a dyskinetic apex. The ejection fraction was estimated to be 20%. Cardiac catheterization demonstrated diffuse coronary artery disease, including a 99% occlusion of the middle right coronary artery, and subtotal occlusion of the proximal left circumflex artery and an estimated 70% stenosis of the left main coronary artery. The left anterior descending artery was 100% occluded at the middle segment and appeared to be an old occlusion, based on morphology. An intra-aortic balloon pump was placed during this catheterization for myocardial support, and a temporary pacemaker was placed. Soon after cardiac catheterization, the patient began to have respiratory difficulty and was electively intubated for impending respiratory failure. The patient was deemed not to be a surgical candidate, based on his current condition and coronary anatomy involvement. Because the patient's condition continued to deteriorate, it was decided to perform percutaneous cardiac intervention in an attempt to salvage any viable myocardium in the face of this ongoing ischemia. Angioplasty and stent placement was used to restore TIMI 3 flow through the right coronary and left circumflex arteries. Stenting of the left main coronary artery provided TIMI 3 flow downstream to an impaired left coronary circulation system, relieving ongoing ischemia from his extensive disease. It should be noted that flow was restored to the left circumflex coronary artery without intervening on the left main; however, this was TIMI 2 flow at best. The importance of proper flow through this segment was demonstrated by restoration of normal sinusrhythm once it was stented open. Presumably, a nutrient branch distal to this segmental stenosis at least partially supplied the atrioventricular node in this patient. Considering the complete occlusion of the middle segment of the left anterior descending artery, optimizing flow through this segment is paramount to maintain sinus rhythm in this patient. Therefore, the left main artery was stented to provide additional support and TIMI 3 flow to the already compromised left circulation. The intra-aortic balloon pump and the temporary pacemaker were removed after the second catheterization. The patient was extubated several days after the intervention. The patient was asymptomatic on discharge from the hospital and remained well 9 months after intervention.

Case 2 was a 52-year-old white female with unstable angina who was transferred to this institution for further management options. She was originally diagnosed with proximal LMCA stenosis and had undergone two separate coronary artery bypass graft operations over the past 2 years for treatment of this disease. Her disease had progressed to dyspnea with minimal exertion and unstable angina. This patient had twice failed surgical treatment and refused further coronary artery bypass grafting. Therefore, stenting of the LMCA lesion was performed, using a paclitaxel-eluding stent, which restored TIMI 3 flow to the distal left coronary artery system. More importantly, it relieved her symptoms of dyspnea and chest pain fully, and the patient was discharged home the day after the intervention. She remained asymptomatic 12 months after intervention.

The above cases both demonstrate that at a high-volume center with experienced physicians, this procedure can be successfully performed with positive outcomes. Furthermore, both of these cases used drug-eluding stents on the LMCA disease. Since publication of the initial recommendations, multiple case reports, retrospective analyses and multicenter trials have been published that demonstrate safe utilization of LMCA intervention with improved mortality rates. (2-4) Drug-eluding stents combined with intravascular ultrasound have revolutionized the manner in which physicians approach percutaneous intervention. Based on the maturation of this technology, it is our suggestion that The American Heart Association/American College of Cardiology consider revising their recommendations, in view of the new evidence, and that further studies involving a large number of patients be considered.

Matthew J. Diamond, DO

Jaspal Gujral, MBBS, FACP

Deepak Kapoor, MD

Medical College of Georgia Augusta, GA

References

1. Smith SC Jr, Dove JT, Jacobs AK, et al. ACC/AHA guidelines for percutaneous coronary intervention (revision of the 1993 PTCA guidelines): executive summary. Circulation 2001; 103:3019.

2. Marso SP, Steg G, Plokker T, et al. Catheterbased reperfusion of Unprotected Left Main Stenosis During Acute Myocardial Infarction (the ULTIMA experience). Am J Cardiol 1999; 83:1513-1517.

3. Nayak AK, Davis R, Reddy HK, et al. Left main coronary artery rotational atherectomy and stenting. South Med J 2000;93:415-423.

4. Ellis SG, Tamani H, Nobuyoshi M, et al. Contemporary percutaneous treatment of unprotected left main coronary stenosis. Circulation 1997;96:3867-3872

A positive attitude may not solve all your problems, but it will annoy
enough people to make it worth the effort.
--Herm Albright