There is hope even for patients with severe blockage of all the three major heart arteries.
Mr A was found to have severe blockage of all the 3 major heart arteries resulting in compromised blood flow to the heart. This caused his heart to be significantly swollen and his pumping action of his left heart chamber (left ventricle or LV) was significantly impaired.
In a normal heart, for every 100 millilitres of blood that flows into the LV, the efficiency of 50% or more means that more than 50% or more of the blood volume that flows into the LV is pumped out of the LV into the aorta, the main arterial channel of the body.
In Mr A’s case, his LV was able to pump only 15% of the blood volume with each heartbeat, creating a strain on the LV and causing him to have breathless and chest tightness with minimal activity.
Another patient, Mr B, was in a similar condition with complete occlusion of 2 major heart arteries and 90% narrowing of the remaining heart artery.
Both Mr A and B were referred to a heart surgeon to consider open heart coronary artery bypass graft surgery (CABG). While Mr A was open to a CABG, Mr B refused a CABG.
Despite Mr A’s willingness to undergo a CABG, the surgeon declined to perform CABG for him citing the evidence from the STICH (Surgical Treatment for Ischaemic Heart Failure) trial. In the latest issue of the Circulation journal, the investigators of the STICH trial reported on the characteristics of the patient, procedural and post-procedural factors that had increased the risk of death following CABG.
The STICH trial looked at patients with severely narrowed heart arteries and moderately impaired LV pump function (heart pump function of 35% efficiency or less as compared to the normal of 50% of more) and compared the outcomes between those who just treated with medication versus those who underwent CABG.
The median follow up for patients in the trial was slightly less than 5 years. At the conclusion of the study, these was no significant difference in terms of death between the 2 treatment groups, with death occurring in 41% of those assigned to medication and 36% of those who underwent CABG. Of those who underwent CABG, 5.1% died within 30 days after CABG and nearly a quarter (23.7%) had at least 1 major complication such as repeat surgery, significant heart failure, new onset life threatening heart rhythm, cardiac arrest, heart attack, stroke or significant deterioration of kidney function. If there were 2 to 3 complications, the risk of death within 30 days was about 1 in 3. If there were 4 complications or more, the risk of death was 59%. It was noted in these patients that once a complication occurs, the likelihood of the patient developing a second complication was high.
The most frequent post-operative complications were worsening kidney function, new onset life threatening heart rhythms, cardiac arrest, repeat surgery and significant heart failure. Given the fact that these patients have swollen hearts with poor heart pump function, it is not surprising that the complication rates are high. The strongest pre-operative and procedural predictors of a poor survival were kidney impairment, significant swelling of the heart, advanced age, pre-operative atrial flutter/ fibrillation (abnormal heart rhythms) and a prolonged surgery time.
As both Mr A and Mr B did not undergo CABG but had a high risk of death if they continued on medication alone, they were given the option of opening the heart arteries with minimally invasive techniques, called angioplasty or percutaneous coronary intervention (PCI), using balloon catheters and stents to open up the severely blocked heart arteries.
They were both initially given a course of medication to improve their heart pump function and to reduce the heart swelling. As both had extremely complicated heart artery disease involving complete occlusion of 2 out of the 3 major heart arteries, the PCI procedures were divided into 2 phases. The first phase involving opening a completely blocked artery to improve blood flow to the heart and to allow the heart function to improve further. The second phase involved opening all the blocked segments in the remaining major heart arteries. The PCI procedures were successfully performed and in both cases, the heart size and the heart function became virtually normal.
While it may have been impossible to provide Mr A and Mr B with alternatives 20 years ago, development in PCI technology has made PCI a possible option. However, these extremely difficult procedures can only be performed successfully with low risk and good long term outcomes by heart specialists who perform complicated PCIs regularly.
However, for Mr A and B, their problems did not end there. Both were discovered incidentally to have a swelling of the aorta, the main arterial channel, in the abdomen. A condition called abdominal aortic aneurysm (AAA). When the aorta becomes swollen, the wall of the aorta becomes thinned out as it expands. Over time, it gets progressively more swollen and may eventually rupture, causing death in most cases. Advances in medical technology has made it possible to treat AAA with minimally invasive techniques.
The procedure involves making small incisions into the groin arteries under anaesthesia and inserting specially constructed cylindrical meshes with an external covering which can be fitted together to join the upper normal segment of the aorta with the 2 main arteries supplying the legs, thereby creating a new channel to allow flow into the legs and isolating the weakened expanded aortic wall of the AAA to prevent further expansion and rupture of the wall.
Mr A agreed to the procedure and it was performed successfully without any complications. Mr B, having felt very much better after the opening of his heart arteries and recovery of his heart function, kept postponing the date of the procedure to treat his AAA. As he did not have any symptoms from his AAA, he did not feel the urgency to have the procedure done despite being warned of the dire consequences of a sudden rupture of his AAA. While overseas, he suddenly developed pain in the abdomen with low blood pressure due to a leak in the AAA. Unfortunately, he never made it back home.
The results of the STICH trial and the experiences of these 2 patients provide some useful take home messages for those patients with severe blockage of their major heart arteries and poor heart pump function :
• Opting for medication alone will result in a high risk of death ;
• In the presence of high risk factors such as with kidney impairment, significant swelling of the heart, advanced age and pre-existing atrial flutter/fibrillation (abnormal heart rhythms), CABG is associated with a high risk of death and has not been shown to be superior to taking medication ;
• If there are no high risk factors and the patient opts for CABG, the choice of a good surgical team is important as prolonged surgical time has been associated with increased risk of complications;
• If the patient opts for PCI, he will have to find a cardiologist who has significant experience in performing complicated PCI procedures, meets the annual competence criteria in terms of volume of the PCIs performed annually, is currently performing these complicated PCI procedures in high volume, has a good safety record and has good long term outcomes; 5) For these patients, there is always a possibility that there will be the presence of abnormal swelling of the aorta (aneurysm) and this should be actively looked for as the aortic aneurysm is usually asymptomatic and can be life threatening.
Hence, even with bad arteries and a bad heart, making good decisions can result in excellent outcomes.