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Indian Journal for the Practising Doctor

CABG at SKIMS - An Initial Experience

Author(s): Lone RA, Ahangar AG, Zubair H, Hussain Z, Dar AM

Vol. 5, No. 6 (2009-01 - 2009-02)

2 – SKIMS, the Sher-i-Kashmir Institute of Medical Sciences, Srinagar, is the only superspeciality tertiary care hospital of the J&K State

Lone RA, Ahangar AG, Zubair H, Hussain Z, Dar AM

Dr. Reyaz A Lone, Dr. Hakeem Zubair, Dr. Zahur Hussain, (Senior Residents), Dr. A. Majeed Dar, (Addl. Professors), Dr. A.G. Ahanger (Professor), Cardiovascular and Thoracic Surgery Department, SK Institrute of Medical Sciences, Srinagar

Correspondence: Dr. Reyaz. A. Lone, MCh (CVTS) CVTS Department, SKIMS, Soura

ISSN: 0973-516X

Abstract

CABG has been the standard surgical procedure for atherosclerotic coronary artery disease. CABG on pump has stood the test of time since the introduction of heart lung machine. The technique off pump has also been performed with comparable results. Our initial experience with a small number of patients is encouraging. Out of the fourteen patients with comparable patient characteristics, five were operated on pump and nine off pump. Majority of our patients (11) had multivessel disease. The cost to patients was 50% less in case of off pump CABG. The average postoperative hospital stay was 1 week shorter in off pump CABG compared to on pump CABG.

Introduction

Coronary artery disease (CAD) in India is showing an increasing trend in the incidence mainly because of the changing lifestyle and dietary habits, that involves a stressful life and diet replete with cholesterol. The commonest underlying cause remains the atherosclerosis. The disease may begin early in life and has been observed microscopically even in infants1. The spectrum of disease extends from subtle chest discomfort to massive acute myocardial infarction. When atherosclerotic plaque decreases the cross sectional area by 75% or more, the resistance to flow becomes significant causing symptoms. Attempts to restore myocardial perfusion have ranged from medical treatment through open surgery to percutaneous interventional procedures. CABG is the commonest operation in developed countries and its demand is increasing in the developing world.

CABG surgery is advised for selected groups of patients with significant narrowing and blockages of the heart arteries (coronary artery disease). CABG surgery creates new routes around the narrowed and blocked arteries, allowing sufficient blood flow to deliver oxygen and nutrients to the heart muscle. CABG surgery is performed to relieve angina in patients who have failed medical therapy and are not good candidates for angioplasty (PTCA). CABG surgery is ideal for patients with multiple narrowings in multiple coronary artery branches, as is often seen in patients with diabetes. CABG surgery has been shown to improve long-term survival in patients with significant narrowing of the left main coronary artery, and in patients with significant narrowing of multiple arteries, especially in those with decreased heart muscle pump function.

The risk of CABG increases with the advancing age of patients, their co-morbidities and the referral of patients after multiple attempts at percutaneous intervention2.

Kolesov performed the first planned CABG on a beating heart; he anastomosed LIMA to left anterior descending artery (LAD) in 19643. For a long time CABG was carried out on a beating heart but the technical difficulty and doubts about anastomoses were major concerns. Cardiac surgery had been revolutionized by the development of CPB- (cardiopulmonary bypass) machine by Gibbon in 1953. CABG was thus performed on CPB which provided a still field. For a long time, the pump was considered an absolute requirement for CABG4,5. Over the years, however, the ‘on pump’ cardiac surgery led to the observation that CPB with associated cardioplegia had its own adverse affects6; hence, renewed interest in the ‘off pump’ CABG. The off-pump technique, also known as OPCAB, is very similar to the conventional Coronary Artery Bypass Grafting (CABG) procedure. OPCAB still utilizes a medial sternotomy, however, the vital difference is that the cardiopulmonary bypass pump is no longer employed.

CABG, both on pump CABG (CABG) and OPCABG, have their proponents. Today 18- 20% of all CABGs are performed ‘off pump’7. The indications8,9 for the off-pump CABG are well documented.

Materials and Methods

We operated 14 patients over a span of 2.5 years from January 2006 to July 2008; both CABG ‘on pump’ and ‘off pump’ were done. Patients were selected on criteria set preoperatively: having good renal function NYHA class <III, and good respiratory reserve (FEV1/FVC>90%). The number of vessel involvement was not a criterion. All patients were operated electively. None of the patients selected had any previous intervention or surgery done on heart. The type of the conduit chosen was also not considered.

All patients were admitted 2 days before the scheduled day of operation. All necessary baseline investigations were done and patients subjected to pre-anaesthetic check up one night prior to the surgery. The baseline investigations included sternal swab cultures, axillary swab cultures, renal function tests, and the liver function tests. All patients, who were selected, had a creatinine level of <2. Any positive cultures were treated with specific antibiotics; patients were deemed fit for operation if repeat cultures were negative. All the patients were required to take bath on the morning of operation and then had their chest painted with betadine 2 hours before the surgery. Repeated painting with betadine is theatre was also done. This was done in order to reduce postoperative wound infection.

Table-1: General Characteristics of Operated Patients

table 1

Aim

The aim of the operation was to obtain complete revascularization by bypassing all severe stenosis defined as 50% reduction in diameter, in all coronary trunks and branches having a diameter of 1mm or more.

Results

Between January 2006 to July 2008, 14 patients were operated. The baseline characteristics of patients are given in Table I. All the patients had a BMI of over 30, majority had hypertension and almost a half were diabetics. The majority (71.5%) comprised of males and most (78.5%) had multivessel involvement. Agewise, the majority belonged to the past 50 year bracket. (table 2).

Table-2: Age distribution of Patients

Age range No. of patients
40-50 2 (14.3%)
51-60 8 (57.1%)
61-70 3 (21.4%)
71-80 1 (7.1%)

Table 3 shows the respective prognosis. The average hospital stay with the off pump procedures was one-half to one-third the on pump CABG. The average short-term cost was also less than halved. There was no mortality in the ‘off-pump group, whle 2 patients (one male and another female) died after the ‘on pump’ procedure. Sternal wound infection was however higher in our procedure.

Table-3: Comparison of Outcome between Off Pump and On Pump CABG.

Parameter Off pump On pump
Hospital stay 1 week 2-3 weeks
Short turn cost 20000 45000
Sternal wound infection 3 2
Death Nil 2

Discussion

CABG is the treatment of choice for multivessel coronary artery stenosis. It provides a complete revascularization option for patients with multivessel and multilesional CAD10. In our study 11 out of 14 patients (78.60%) had multivessel involvement. CAD is known to show an increasing incidence with rising age. Our patients had an average age of 62 +5 years, with most of them (57%) falling in the 51-70 years age group. As expected, the disease was more prevalent in males and most of the patients had multiple vessel diseases. LAD was the commonest vessel involved followed by RCA or Lt. cx, in that order of frequency. This was in accordance with the study conducted by Berger et al11.

We subjected patients both to ‘on pump’ and ‘off pump’ bypass surgery. Five patients were operated on-pump and nine off-pump. Our experience with the off pump bypass surgery was better than with the on pump bypass. One of the 14 patients had a neurological complication in the form of seizures; CT head done subsequently did not show any significant lesion in the brain. This patient was operated on pump. CPB has been indicated in neurologic complication that may arise in a patient after cardiac surgery12,13,14. Gender difference in patients also had an impact on the nature of outcome. Our sample had two mortalities, one from acute renal failure and the second due to ventricular dysrrhythmias post surgery. One patient was male and the other a female. Gender differences in outcome have been shown to exist in CABG. Most studies have noted greater in-hospital mortality in women than men. Women also experience more frequent complications and an early mortality after revascularization6. Our study had equal mortality in both sexes. The reason for this could be the small size of our study sample. Most of the earlier studies had large sample size and had better differentiation in outcomes in sexes. Moreover, this was our initial experience with CABG and therefore, early phase of the leaning curve.

In terms of cost, we found that the on pump surgery was more costly than the off pump CABG. Numerous studies have substantiated this finding, by comparing ‘on pump’ with ‘off pump’ CABG2 and comparing CABG with stenting. In the long run off pump CABG has been found to be more cost effective than onpump CABG and stenting. Our study also noted a high rate of sternal wound infection. Five of our patients who developed infection (2 operated on pump and 3 off pump) had superficial, sternal wound infection. Out of these 5 patients, 2 had diabetes. One of the mortalities we had, had sternal wound infection also. The higher rate of sternal wound infection was in sharp contrast to an earlier study which has shown 1-4% of patients getting it8. Again, the effect of a smaller sample could not be ruled out, though other factors could be at interplay. From the above discussion it is amply clear that our initial experience of CABG at SKIMS is comparable to other centres where CABG is routinely being performed. Some of our observations have been consistent with similar other studies but many observations, like a higher wound infection rate and a high rate of mortality, are thought provoking and require further investigation. Although a smaller sample size could be a confounder, however, it has to be borne in mind that complication rate is usually higher in the earlier experience with CABG. Our endeavour is to continue to improve with subsequent experience and match international standards within the scarce resources that a hospital in developing countries can have.

Conclusion

From our initial experience with CABG patients, the ‘off pump’ CABG is a safe and cost-effective treatment of the static atherosclerotic coronary artery disease. It is well tolerated hemodynamically with minimal postoperative morbidity and low mortality.

References

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  2. Raghuram AR. Off-pump CABG: A review. Intern J Cardiol 2003;2(1).
  3. Kolesov VI. Mammary artery: Coronary artery anastomosis as method of treatment for angina pectoris. J of Thor Cardiovasc Surg 1967;54:535-44.
  4. Ankeney JL. To use or not to use the pump oxygenator in coronary bypass operations. Ann Thorac Surg 1975;19:108-8.
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  11. Berger RL, Stary HC:Anatomic assessment of operability by the saphenous vein bypass operation in coronary artery disease. N Engl J Med 1971, 285:24852
  12. Redmond JM,Greene PS,Goldsborough MA etal:Neurological injury in cardiac surgical patients history of stroke: Ann. Thorac Surg 1996:61:427
  13. Westaby S,Johnson P,Parry AJ, etal:Serum S100 protien:a potential marker for cerebral events during CPB. Ann. Thorac Surg 1996:61:8892
  14. Smith PL:The cerebral consequences of coronary artery bypass surgery. Ann. R Coll Surg Engl 1998:70:212-6 Original
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