Dr. Anderson, Dr. Pairolero, members of the Society and guests:
We all recognize by now from papers that have appeared in the literature over the last several years that transmyocardial laser revascularization creates channels in the myocardium that have been shown to significantly improve angina in 75% of patients in all clinical studies that have examined this therapy.
Approximately 6 to 7 million people in the United States suffer from angina. 5.5 million are adequately treated by changes in lifestyle and pharmacological therapy. One million patients undergo coronary bypass, angioplasty, and stenting procedures. However, for patients who are refractory to medical therapy and in whom various approaches to revascularization are not possible because of failed prior procedures, diffuse coronary atherosclerosis, distal stenoses, or very small coronary arteries, recurrent disabling angina constitutes a frustrating and costly burden to patients, caregivers, and health care systems nationwide. About 150,000 Americans annually fall under this category of end-stage coronary artery disease.
For the two fundamental goals in the treatment of coronary artery disease, relief of angina is critical to returning patients to a normal lifestyle. Transmyocardial revascularization as a treatment for angina has been very successful for patients with chronic angina, who are refractory to medical therapy and who meet the criteria on this slide. These are no option patients who have no viable alternative in the treatment of their very poorly controlled angina.
There is a group of anginal patients; however, who present an even greater dilemma, not only with control of their angina, but to physicians and hospitals nationwide. These are patients with unmanageable, unstable angina defined in our study as patients who have been on intravenous anti-anginal therapy for at least seven days, with at least 3 unsuccessful attempts to wean them off anti-anginal medications. Many patients were taken, therefore, directly from the intensive care unit to the operating room.
The study that we are reporting on today was designed to examine two groups of these no option patients - one with chronic angina and one with a much more severe form of angina; unmanageable, unstable angina. Both groups underwent transmyocardial laser revascularization as sole therapy and were followed for twelve months.
In both groups the procedure was performed through a left thoracotomy on the beating heart. The mechanism used for choosing sites on the heart for laser therapy, however, was different in the two groups. For the more stable, chronic angina patient, nuclear scans identified areas of ischemia on the heart. For unmanageable, unstable anginal patients, scans were usually not available for these bedridden patients. Sites for laser were chosen by knowledge of the electrocardiogram, looking at ischemic areas, transesophogeal echo observations, looking for contractility and a lack of thinning of the myocardium and a knowledge of the coronary angiograms.
The actual demographics of the two groups of patients treated by transmyocardial laser revascularization were very similar. A majority had had coronary artery bypass or angioplasty procedures, and prior myocardial infarcts and episodes of congestive heart failure were frequent.
There were more females in the unmanageable unstable group. Ages were almost identical in the two groups. The mean ejection fraction in the two groups was different; however, on statistical analysis this did not quite reach a level of statistical significance. All patients in the unmanageable, unstable group had Class 4 angina; whereas, 80 percent of patients in the chronic angina protocol group had a similar anginal class.
Turning from demographics now to results. The results for the two groups were significantly different looking at mortality. Mortality rates in the perioperative interval, for chronic angina patients were significantly different at 3 percent when compared with the unmanageable, unstable anginal patients who had a mortality of 17 percent. After the first month, however, the death rate of the two groups was similar. In both groups 85 percent of deaths were from cardiac causes. Two patients in the unmanageable, unstable group died on the day of surgery- one from ventricular fibrillation and one from profound shock.
One of the drawbacks in looking at any therapy of unmanageable, unstable angina is that there are no good studies in the literature on the natural history of this group of patients when treated with modern day therapy. However, cardiologists in this country, who have classified unstable angina, and who have done this for us in the literature, believe that the mortality in this group of patients approaches 40 -50 percent at 6-12 months. So our cardiology colleagues feel patients in this category are at high risk for death.
The non-lethal perioperative complications were similar in the two groups except for acute myocardial infarct and arrhythmias which were significantly higher in the unmanageable, unstable group of patients. At the time of enrollment, all patients in the unmanageable, unstable anginal group had Class 4 angina and according to the Canadian classification, Class 4 angina is defined as inability to carry out any activity without angina and sometimes angina at rest. Whereas, 80 percent of chronic angina patients had Class 4 angina, approximately, 75 percent of patients from both groups no longer had Class 3 or Class 4 angina out to 12 months of follow-up.
No patients at baseline were without angina or had Canadian angina Class 1. Now Class 1 angina is defined according to the Canadian classification as ordinary physical activity does not cause angina. At all follow-up intervals about 50 percent of patients could resume normal activity levels without angina.
Now, I think we have to remind ourselves again that pre-operatively the unmanageable, unstable anginal group of patients represented a group of patients who had gone to the operating room from the intensive care unit, unable to be weaned from intravenous anti-anginal medications. About 50 percent of patients in both groups had decreased their anti-anginal medications on follow-up and patients who had presented initially with unstable, unmanageable angina had equally good response to a reduction in medication as did the chronic angina protocol patients.
In summary, in the treatment of disabling angina, transmyocardial laser revascularization is equally effective in patients with chronic angina and patients with unstable, unmanageable angina. The patients carry a definitely high risk. The angina and quality of life improvements, once they are past the perioperative interval, however are significant and comparable to patients with chronic angina. The actual ability to recommend the therapy is hampered by the lack of any good natural history studies on this group of unmanageable, unstable anginal patients. However, our cardiologists who deal with these patients feel that the mortality remains extremely high in this group of patients. So with that in mind, TMR may be an option for patients with uncontrolled angina who otherwise have no other options.
I want to thank the Society for the privilege of addressing you today. Thank you.