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Minimally invasive direct coronary artery bypass grafting: midterm results and quality of life
Minimally Invasive Direct Coronary Artery Bypass Grafting: Midterm Results and Quality of Life Paolo Biglioli, MD, Carlo Antona, MD, Francesco Alamanni, MD, Alessandro Parolari, MD, PhD, Thomas Toscano, MD, PhD, Giulio Pompilio, MD, and Gianluca Polvani, MD Department of Cardiac Surgery, University of Milan, Centro Cardiologico, Fondazione I Monzino IRCCS, Milan, Italy
Background. There is increasing interest in minimally invasive direct coronary artery bypass grafting (MIDCABG); however, there is still little information about midterm results and postoperative quality of life. Methods. From March 1995 to March 1998, 64 patients underwent MIDCABG at our hospital. Their mean age was 60 ⴞ 9.5 years; 22 (34.4%) had unstable angina. All patients were followed-up by both direct visit and questionnaire to assess the postoperative quality of life. Results. There were no perioperative deaths nor conversions to sternotomy; the perioperative myocardial infarction rate was 1/64 (1.6%). Predischarge angiography showed overall and unobstructed patency rates of 96.8% (62 of 64)
and 93.8% (60 of 64), respectively. At follow-up (25 ⴞ 11.4 months) actuarial survival was 100%, and survival free of myocardial infarction was 98.4% ⴞ 1.6% at 3 years. Both the Physical Activity Score and the Psychological General Well-being Index improved significantly after the operation, with percentage improvements of 31% and 23%, respectively, at 12 months postoperatively. Conclusions. In selected patients MIDCABG can be a reliable and safe option. Patients who undergo this procedure are free of major complications and enjoy a good quality of life after surgery. (Ann Thorac Surg 2000;70:456 – 60) © 2000 by The Society of Thoracic Surgeons
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Patients and Methods
he last 5 years have shown increasing enthusiasm in less invasive myocardial revascularization procedures, especially because of the possible reduction in patients morbidity rates by lowering surgical trauma. In particular, the use of the left internal thoracic artery to revascularize the left anterior descending (LAD) coronary artery through a small left thoracotomy without the use of cardiopulmonary bypass (minimally invasive coronary artery bypass grafting, or MIDCABG) has become the most popular less invasive myocardial revascularization procedure among surgeons worldwide, as it allows one to perform myocardial revascularization with the best performing arterial graft (ie, the internal thoracic artery) on the most important coronary artery (LAD), and simultaneously it reduces surgical trauma. This can be accomplished by avoiding both the risks related to the use of the cardiopulmonary bypass and the pain connected with the use of median sternotomy so that the postoperative course and recovery can be facilitated. However, there is still little information about follow-up results, especially concerning the quality of life of patients operated on with this technique. In this article we report early and midterm results of 64 consecutive patients who underwent MIDCABG at our hospital, with special emphasis on possible improvements in quality of life. Accepted for publication Jan 20, 2000. Address reprint requests to Dr Parolari, Department of Cardiac Surgery, University of Milan, Centro Cardiologico, Fondazione I Monzino IRCCS, Via Parea, 4, 20138, Milan, Italy; e-mail: aparolari@ cardiologicomonzino.it.
© 2000 by The Society of Thoracic Surgeons Published by Elsevier Science Inc
Patient Population From March 1995 to March 1998, 2,508 patients underwent elective nonemergent primary coronary artery bypass grafting procedures (CABG) at our institution. Of these, 275 (11.0%) patients underwent CABG without cardiopulmonary bypass with the beating heart and median sternotomy, whereas 64 (2.6%) patients were selected to undergo MIDCABG. Mean age was 60 ⫾ 9.5 years. In all, 45 patients (71.3%) were male, 22 (34.4%) had unstable angina, 24 (37.5%) history of hypertension, 4 (6.3%) insulin-dependent diabetes mellitus, 4 (9.7%) chronic renal failure, 2 (3.1%) previous stroke, and 3 (4.7%) previous TIA. A total of 25 patients (39.1%) had a previous MI (⬎ 3 months), 11 (17.2%) a recent MI (⬍ 3 months), and 13 (20.3%) had previously undegone percutaneous transluminal coronary angioplasty (PTCA).
Surgical Indications At our hospital there were two different categories of possible indications for MIDCABG. ELECTIVE INDICATIONS. Candidates for the MIDCABG procedure were considered to be those patients with isolated LAD disease if: (1) a PTCA (with or without stent) was not considered feasible because of technical aspects such as proximal or complex lesions, or total LAD occlusion; (2) a restenosis after a previous PTCA (with or without stent) had occurred; or (3) the cardiologist or the patient asked for the minimally invasive surgical procedure.
0003-4975/00/$20.00 PII S0003-4975(00)01371-0
Ann Thorac Surg 2000;70:456 – 60
NECESSITY INDICATIONS. Candidates for MIDCABG could also be patients with multiple vessel disease if it was felt that the surgical trauma of a standard CABG procedure could increase prohibitively the perioperative risk. Assuming that the LAD lesion had to be suitable for surgery, the other coronary lesions had to show one or more of the following features: (1) occluded and refilled by collateral circulation; (2) going to previously infarcted territories; or (3) not graftable because of technical aspects (eg, distal stenoses with small coronary size, or heavy calcifications).
Surgical Contraindications and Exclusions Contraindications to MIDCABG were the following: (1) a small LAD (internal size ⬍ 1.5 mm); (2) a diffusely calcified LAD; or (3) an intramyocardial LAD. All of these features could be suspected preoperatively by careful preoperative assessment of the coronary angiography before surgery. In our series, 52 patients (81.1%) underwent MIDCABG for elective reasons, namely, because of an isolated lesion of the left anterior descending artery, whereas the remaining 12 patients (18.9%) underwent the procedure for necessity reasons; they were affected by double-vessel (9 patients, 14.1%) or triple-vessel (3 patients, 4.7%) disease.
Surgical Technique Surgical technique was as previously described [1]. Of note, in all of these patients the left internal mammary artery (LIMA) was harvested under direct vision and a special spreader (Autosuture International Inc, Norwalk, CT) was routinely adopted starting from November 1996 (case 30) and used together with a LAD stabilizer.
Angiographic and Doppler Control An echo-Doppler study of LIMA patency was performed within 1 week and every 6 months postoperatively: the LIMA-to-LAD Doppler flow velocity was evaluated using an echo-color Doppler measurement system (Acuson 128 XP10 ART; Acuson Inc, Mountain View, CA), as previously described [2, 3]. Moreover, before discharge all patients underwent a postoperative angiographic reinvestigation of LIMA-to-LAD grafts.
Quality of Life The patients completed two self-administered questionnaires for the evaluation of their quality of life, namely, the Physical Activity Score and the Psychological General Well-being Index. The Physical Activity Score is a part of an anginaspecific questionnaire, the Angina Pectoris Quality of Life Questionnaire, which contains 25 questions. The last nine questions of the Questionnaire cover leisure activity and physical limitations, and the six questions for the self-estimation of physical abilities and limitations are the body of the Physical Activity Score. Each response is graded from 1 to 6, and the average value for all six questions is calculated, with the higher value representing the greater degree of impaired ability [4].
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The Psychological General Well-being Index was initially constructed to measure subjective well-being or distress [5] and has been used for studies in hypertension [6], angina pectoris and cardiac surgery [7–14], menopausal disorders [15], and gastrointestinal diseases [16]. It comprises 22 items that address six different dimensions of the well-being of each patient: anxiety (five items), depressed mood (three items), positive well-being (four items), self-control (three items), vitality (four items), and general health (three items). Every response can be graded from 1 to 6 (total range, 22 to 132), with the greater value corresponding to superior well-being [5]. The wellbeing score can be affected by factors such as sex and gender. In a study performed in a normal, nonselected European population, women tended to have lower scores than men, and patients 30 to 60 years of age had relatively lower scores than younger or older patients [17]. The questionnaires were mailed to all patients before surgery and were returned at the time of hospitalization for MIDCABG. The same questionnaires were then mailed to patients 6 and 12 months after surgery. All of the questionnaires were validated carefully and tested for reliability.
Follow-up Follow-up information, which was available for 100% of the patients, was obtained by direct examination of the patient. The date of the last inquiry was March 1999. The following end points were collected for each patient: (1) survival; (2) acute myocardial infarction-free survival; (3) angina-free survival; (4) redo-free survival; (5) PTCA-free survival; (6) PTCA on LAD-free survival; (7) redo or PTCA-free survival; (8) survival free from any new hospitalization for cardiac causes; (9) survival free of cardiac events (acute myocardial infarction [AMI], redo, PTCA, angina, or hospitalization for cardiac causes).
Statistical Analysis All continuous data are expressed as mean ⫾ SD (when indicated, the median is reported in brackets); categorical variables are reported as percentages. A commercial statistical software package (SPSS for Windows, version 8.0, SPSS Chicago, IL) was used for data analysis. Continuous variables were tested with the nonparametric Mann-Whitney test. Survival rates for the entire patient population were determined by Kaplan-Meier survival analysis, and the estimated survival proportions are reported plus or minus the standard error of the estimates. A statistical probability of less than 0.05 was considered as indicating significance.
Results Early Results All patients underwent MIDCABG through a left anterior thoracotomy; in all cases a LIMA-to-LAD anastomosis was performed on a beating heart; no conversions to sternotomy were performed. The LAD occlusion time was 25.7 ⫾ 7.8 minutes, whereas the anastomosis time was 18.4 ⫾ 6 minutes. The occlusion of the LAD never caused life-
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Ann Thorac Surg 2000;70:456 – 60
Table 1. Average Physical Activity Scores Before and After Minimally Invasive Direct Coronary Artery Bypass Grafting
Average score Percent change
Before Surgery
6 Months After Surgery
12 Months After Surgery
4.2 ⫾ 0.9 (4.4)
3.0 ⫾ 1.1 (3.1)a ⫺28.5%
2.9 ⫾ 0.7 (3.1)a ⫺31.0%
Scores are reported as mean ⫾ SD (median in parentheses). a
p ⬍ 0.01 vs before surgery.
Negative percent change values indicate improvement.
threatening ventricular arrhythmias or major hemodynamic changes; in no case was an IABP or emergency CPB needed. Surgery time was 2.3 ⫾ 0.5 hours and the wound length at the end of surgery was 10.5 ⫾ 1.2 cm; in one case only (1.6%) the thoracotomy was enlarged up to 16 cm because of an abnormally lateral LAD. No perioperative deaths occurred. One patient (1.6%) showed perioperative myocardial septal infarction without hemodynamic deterioration and 3 patients (4.7%) underwent reoperation for bleeding. The mean ventilatory support time and the mean ICU stay were 7 ⫾ 6.4 hours and 23 ⫾ 10 hours, respectively. Postoperative length of stay was 5.9 ⫾ 1.5 days.
Graft Patency Studies Predischarge echo-Doppler study of the LIMA showed a severe impairment of flow in 4 patients (6.3%), characterized by a systolic velocity in the LIMA graft of less than 10 cm/s and a loss of the diastolic component. The graft angiography performed in these patients showed occlusion of the LIMA to LAD graft in two cases and a significant (⬎ 70%) anastomotic stricture in the remaining two cases. One of these patients underwent redo CABG with full sternotomy, cardiopulmonary bypass, and cardioplegic arrest, whereas in the remaining 3 patients a percutaneous angioplasty resolved the anastomosis problem. Predischarge MIDCABG angiographic patency rates were 62 of 64 (96.8%) for overall patency and were 60 of 64 (93.8%) for perfect patency of the grafts. Follow-up studies performed every 6 months with the echo-Doppler technique showed the persistence of similar blood flow patterns of the LIMA grafts with respect to the early reinvestigation, with no significant variations in the flow characteristics in any single graft.
Measurement of Quality of Life The Physical Activity Score improved significantly after the operation, with a percentage improvement of 28.5% and 31% at 6 and 12 months, respectively (Table 1). The same behavior was shared by the Psychological General WellBeing Index, which improved 17.9% and 23% at 6 and 12 months, respectively (Table 2); the analysis of the six different subscales of the test revealed significant improvements in anxiety, positive well-being, vitality, and general health (Fig 1).
Follow-up Studies Average follow-up was 25 ⫾ 11.4 months (median, 21). Estimates of overall survival and survival free estimates of cardiac-related events are reported in Table 3. Of note, 3-year survival was 100%, AMI-free survival 98.4% ⫾ 1.6%, and angina-free survival 91.8% ⫾ 4.8%.
Comment Less invasive cardiac surgery is a new and significantly different approach to treat a variety of cardiac surgery procedures, and MIDCABG performed with smaller incisions (usually thoracotomies) and without cardiopulmonary bypass is becoming more and more popular. The reasons for the success of these procedures are shorter hospital stay, rapid recovery, faster return to activity, reduced patient morbidity, and less postoperative pain than with standard procedures [18 –20]. Among the new techniques to treat coronary artery disease, MIDCABG has rapidly become the most popular technique used to revascularize the most important coronary artery (LAD) with the most important arterial conduit (LIMA), which is the strongest predictor for long-term and redo-free survival after surgical myocardial revascularization [21, 22]. The maturation of experience in this field and the continuous improvement in techniques and instruments (especially stabilization devices) have allowed surgeons to perform the LIMA-to-LAD anastomosis on a beating heart through a small thoracotomy in a comfortable and reproducible way [23]. It is now becoming clear that early patency rates for this operation in coronary patients are approaching the patency rates for the same anastomosis performed on bypass and with cardioplegic arrest; in fact, the recent results of
Table 2. Average Total Scores for the Psychological General Well-Being Index Before and After Minimally Invasive Direct Coronary Artery Bypass Grafting Before Surgery Average score Percent change
84.3 ⫾ 10.4 (82.4)
Scores are reported as mean ⫾ SD (median in parentheses). a
p ⬍ 0.01 vs before surgery.
Positive percent change values indicate an improvement.
6 Months After Surgery
12 Months After Surgery
99.4 ⫾ 11.1 (98.8)a 17.9%
104.0 ⫾ 7.9 (105.5)a 23.0%
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BIGLIOLI ET AL MIDCABG: MIDTERM RESULTS
Fig 1. Bar graph of the six different domains of the Psychological Well-Being Index (PGWBI) as assessed before and 1 year after minimally invasive coronary artery bypass grafting (*p ⬍ 0.01 1-year follow-up vs preoperative evaluation).
this relatively new technique document overall early patency rates exceeding 95% [23–25]. Previous studies have also shown that conventional coronary bypass surgery procedures significantly improve quality of life in patients soon after surgery [7–9] and that, in patients with multivessel disease, coronary surgery yields a better quality of life than coronary angioplasty. The investigators of the Bypass Angioplasty Revascularization Investigation (BARI) trial [10] documented better improvement in both functional status and emotional health during 3 years of follow-up of patients undergoing CABG for multivessel coronary disease. Furthermore, the quality of life is also improved in subgroups of patients with coronary artery disease presenting with risk factors or comorbidities such as hypertension [11] or diabetes [12], or in octogenarians [13]. However, little information is available on midterm clinical results and especially on quality of life after MIDCABG; to our knowledge, only Calafiore and colleagues [26] reported a 27-month survival of 97.1% ⫾
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0.7% and an event-free survival of 89.4% ⫾ 1.2% after this procedure. The aim of our study was to provide more information about the outcome of patients who undergo this new procedure and, especially, to assess possible improvements in their quality of life. In fact, during the past years, the need to assess how patients feel has developed, and prior evaluations of quality of life by means of surrogate end points such as freedom from angina or of return to work after surgery have become unsatisfactory. For that reason the use of standardized questionnaries has been introduced to assess changes in quality of life in cardiovascular medicine and, especially, therapeutic options for coronary artery disease [4 –14]. This study documents how patients undergoing MIDCABG showed a consistent improvement in their quality of life as assessed by the Physical Activity Score and the Psychological General Well-Being Index, two of the commonly employed batteries of tests to assess changes in quality of life after coronary surgery [11, 12, 14]. Furthermore, the results obtained with MIDCABG seem to compare favorably, in terms both of survival and of event-free survival, with interventional cardiology procedures (PTCA on LAD). In fact, for angioplasty on LAD previous studies document 1- and 3-year survival rates of 97% and 95%, respectively, angina-free survival rates at 1 year of 90% when a stent was used, and of 75% for PTCA without a stent, angina-free survival of 75% at 3 years when using conventional interventional cardiology techniques, and an event-free survival at 1 year of 87% for PTCA with stent and of 70% for PTCA [27, 28]. One of the possible criticisms of this study is that both patients with elective and necessity indications to CABG were assessed together, and this could have affected the possible recurrence of symptoms, the need for new cardiac procedures, or the magnitude of the possible improvements in the quality of life. However, the assessment of the same end points for the patients by indication to surgery (elective vs necessity) could not show any significant difference in event-free survival rates or in the percentage improvement of the tests administered to assess the quality of life (data not shown). The fact that both patients with elective and necessity indications had
Table 3. Survival and Event-Free Survival Rates of Patient Population Variable Patients at risk Survival AMI-free survival Redo-free survival PTCA-free survival PTCA- to LAD–free survival Redo– or PTCA–free survival Angina-free survival New hospitalization–free survival Cardiac event–free survival AMI ⫽ acute myocardial infarction;
1 Year
2 Years
3 Years
64 100% 98.4% ⫾ 1.6% 98.4% ⫾ 1.6% 92.2% ⫾ 3.4% 95.3% ⫾ 2.6% 93.8% ⫾ 3.0% 98.4% ⫾ 1.6% 96.9% ⫾ 2.2% 90.6% ⫾ 3.6%
47 100% 98.4% ⫾ 1.6% 98.4% ⫾ 1.6% 92.2% ⫾ 3.4% 95.3% ⫾ 2.6% 93.8% ⫾ 3.0% 95.2% ⫾ 3.6% 96.6% ⫾ 2.2% 86.9% ⫾ 5.5%
22 100% 98.4% ⫾ 1.6% 98.4% ⫾ 1.6% 92.2% ⫾ 3.4% 95.3% ⫾ 2.6% 93.8% ⫾ 3.0% 91.8% ⫾ 4.8% 96.6% ⫾ 2.2% 86.9% ⫾ 7.5%
LAD ⫽ left anterior descending artery;
PTCA ⫽ percutaneous transluminal coronary angioplasty.
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similar event-free rates and similar percentage improvement in well-being adds further support to the pivotal role of the LIMA to LAD anastomosis in myocardial surgical revascularization. In other words, the strength of this anastomosis seems by far to be most important in determining the fate of patients undergoing CABG. Another limitation of the study is that it did not include a control group, and for this reason it is impossible to determine how much of the change in quality of life was due to this new surgical procedure and how much was due to other factors such as the simple follow-up of the patients. However, it was believed to be unethical to deny the chance for revascularization to a cohort of patients who show their main lesion on the most important coronary vessel and target for revascularization. Additional prospective comparisons of different ways to manage LAD disease (PTCA, conventional CABG, or MIDCABG) will be needed to document possible differences in postoperative outcomes. In conclusion, MIDCABG is an effective way to improve the quality of life and to provide angina relief for selected subgroups of coronary patients. The midterm survival and event-free survival rates achievable with this surgical option are encouraging, even if longer follow-up times are needed for a more precise assessment of the results of this surgery.
References 1. Antona C, Pompilio G, Lotto AA, et al. Video-assisted minimally invasive coronary bypass surgery without cardiopulmonary bypass. Eur J Cardiothorac Surg 1998;14:S62–7. 2. Calafiore AM, Di Giammarco G, Teodori G, et al. Left anterior descending coronary artery grafting via left anterior small thoracotomy without cardiopulmonary bypass. Ann Thorac Surg 1996;61:1658– 65. 3. Cartier R, Dias OS, Pellerin M, Hebert Y, Leclerc Y. Changing flow pattern of the internal thoracic artery undergoing coronary bypass grafting: continuous-wave Doppler assessment. J Thorac Cardiovasc Surg 1996;112:52– 8. 4. Wilson A, Wiklund I, Lahti T, Wahl M. A summary index for the assessment of quality of life in angina pectoris. J Clin Epidemiol 1991;44:981– 8. 5. Dupuy H. The Psychological General Well-Being (PGWB) Index. In: Wenger NK, Mattson ME, Furberg CD, Elison J, eds. Assessment of quality of life in clinical trials of cardiovascular therapies. New York: Le Jacq Publishers, 1984:170– 83. 6. Croog SH, Levine S, Testa MA, et al. The effects of antihypertensive therapy on the quality of life. N Engl J Med 1986; 314:1657– 64. 7. Sjoland H, Caidahl K, Wiklund I, et al. Impact of coronary artery bypass grafting on various aspects of quality of life. Eur J Cardiothorac Surg 1997;12:612–9. 8. Klersy C, Collarini L, Morellini MC, Cellino F. Heart surgery and quality of life: a prospective study on ischemic patients. Eur J Cardiothorac Surg 1997;12:602–9. 9. Jaarsma T, Kastermans MC. Recovery and quality of life one year after coronary artery bypass grafting. Scand J Caring Sci 1997;11:67–72.
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10. Hlatky M, Rogers WJ, Johnstone I, et al. Medical care costs and quality of life after randomization to coronary angioplasty or coronary bypass surgery. N Engl J Med 1997;336:92–9. 11. Sjoland H, Hartford H, Caidahl K, et al. Improvement in various estimates of quality of life after coronary artery bypass grafting in patients with and without a history of hypertension. J Hypertens 1997;15:1033–9. 12. Herlitz J, Sjoland H, Haglid M, et al. Impact of a history of diabetes mellitus on quality of life after coronary bypass grafting. Eur J Cardiothorac Surg 1997;12:853– 61. 13. Sollano JA, Rose EA, Williams DL, et al. Cost-effectiveness of coronary artery bypass surgery in octogenarians. Ann Surg 1998;228:297–306. 14. Herlitz J, Haglid M, Wiklund I, et al. Improvement in quality of life during 5 years after coronary artery bypass grafting. Coronary Artery Dis 1998;9:519–26. 15. Wiklund I, Karlberg J, Mattson L. Quality of life during transdermal oestradiol therapy in postmenopausal women. Am J Obstet Gynecol 1993;168:824–30. 16. Dimenas E, Carlsson G, Glise H, et al. Well being and gastrointestinal symptoms among patients referred to endoscopy owing to suspected duodenal ulcer. Scand J Gastroenterol 1995;30:1046–52. 17. Dimenas E, Carlsson G, Glise H, Israelsson B, Wiklund I. General well-being and subjective symptoms among a randomly selected normal Swedish population. Scand J Gastroenterol 1996;31(Suppl 211):8–13. 18. Arom KV, Emery RW, Nicoloff DM, et al. Minimally invasive direct coronary artery bypass grafting: experimental and clinical experiences. Ann Thorac Surg 1997;63:48–52. 19. Bredee JJ, Jansen EW. Coronary artery bypass grafting without cardiopulmonary bypass. Curr Opin Cardiol 1998; 13:476– 82. 20. Magovern JA, Benckart DH, Landreneau RJ, et al. Morbidity, cost, and six-month outcome of minimally invasive direct coronary artery bypass grafting. Ann Thorac Surg 1998;68: 1224–9. 21. Calafiore AM, Teodori G, Di Giammarco G, et al. Minimally invasive coronary artery bypass grafting on a beating heart. Ann Thorac Surg 1997;63:S72–5. 22. Loop FD, Lytle BW, Cosgrove DM, et al. Influence of the internal mammary artery graft on 10 year survival and other cardiac events. N Engl J Med 1986;314:1– 6. 23. Calafiore AM, Teodori G, Di Giammarco G, et al. The LAST operation: technique and result before and after the stabilization era. Ann Thorac Surg 1998;66:998 –1001. 24. Holubkov R, Zenati M, Akin JJ, Erb L, Courcoulas A. MIDCAB characteristics and results: the cardiothoracic systems (CTS) registry. Eur J Cardiothorac Surg 1998;1:S25–30. 25. Diegeler A, Falk V, Martin M, et al. Minimally invasive bypass grafting without cardiopulmonary bypass: early experience and follow-up. Ann Thorac Surg 1998;66:1022–5. 26. Calafiore AM, Di Giammarco G, Teodori G, et al. Midterm results after minimally invasive coronary surgery (LAST operation). J Thorac Cardiovasc Surg 1998;115:763–71. 27. Versaci F, Gaspardone A, Phil M, et al. A comparation of coronary-artery stenting with angioplasty for isolated stenosis of the proximal left anterior descending coronary artery. New Engl J Med 1997;336:817–22. 28. Berg JM, Gin MTJ, Ernest SMPG, et al. Ten-year follow-up of percutaneous transluminal coronary angioplasty for proximal left anterior descending coronary artery stenosis in 351 patients. J Am Coll Cardiol 1996;28:82– 8.
Background. There is increasing interest in minimally invasive direct coronary artery bypass grafting (MIDCABG); however, there is still little information about midterm results and postoperative quality of life. Methods. From March 1995 to March 1998, 64 patients underwent MIDCABG at our hospital. Their mean age was 60 ⴞ 9.5 years; 22 (34.4%) had unstable angina. All patients were followed-up by both direct visit and questionnaire to assess the postoperative quality of life. Results. There were no perioperative deaths nor conversions to sternotomy; the perioperative myocardial infarction rate was 1/64 (1.6%). Predischarge angiography showed overall and unobstructed patency rates of 96.8% (62 of 64)
and 93.8% (60 of 64), respectively. At follow-up (25 ⴞ 11.4 months) actuarial survival was 100%, and survival free of myocardial infarction was 98.4% ⴞ 1.6% at 3 years. Both the Physical Activity Score and the Psychological General Well-being Index improved significantly after the operation, with percentage improvements of 31% and 23%, respectively, at 12 months postoperatively. Conclusions. In selected patients MIDCABG can be a reliable and safe option. Patients who undergo this procedure are free of major complications and enjoy a good quality of life after surgery. (Ann Thorac Surg 2000;70:456 – 60) © 2000 by The Society of Thoracic Surgeons
T
Patients and Methods
he last 5 years have shown increasing enthusiasm in less invasive myocardial revascularization procedures, especially because of the possible reduction in patients morbidity rates by lowering surgical trauma. In particular, the use of the left internal thoracic artery to revascularize the left anterior descending (LAD) coronary artery through a small left thoracotomy without the use of cardiopulmonary bypass (minimally invasive coronary artery bypass grafting, or MIDCABG) has become the most popular less invasive myocardial revascularization procedure among surgeons worldwide, as it allows one to perform myocardial revascularization with the best performing arterial graft (ie, the internal thoracic artery) on the most important coronary artery (LAD), and simultaneously it reduces surgical trauma. This can be accomplished by avoiding both the risks related to the use of the cardiopulmonary bypass and the pain connected with the use of median sternotomy so that the postoperative course and recovery can be facilitated. However, there is still little information about follow-up results, especially concerning the quality of life of patients operated on with this technique. In this article we report early and midterm results of 64 consecutive patients who underwent MIDCABG at our hospital, with special emphasis on possible improvements in quality of life. Accepted for publication Jan 20, 2000. Address reprint requests to Dr Parolari, Department of Cardiac Surgery, University of Milan, Centro Cardiologico, Fondazione I Monzino IRCCS, Via Parea, 4, 20138, Milan, Italy; e-mail: aparolari@ cardiologicomonzino.it.
© 2000 by The Society of Thoracic Surgeons Published by Elsevier Science Inc
Patient Population From March 1995 to March 1998, 2,508 patients underwent elective nonemergent primary coronary artery bypass grafting procedures (CABG) at our institution. Of these, 275 (11.0%) patients underwent CABG without cardiopulmonary bypass with the beating heart and median sternotomy, whereas 64 (2.6%) patients were selected to undergo MIDCABG. Mean age was 60 ⫾ 9.5 years. In all, 45 patients (71.3%) were male, 22 (34.4%) had unstable angina, 24 (37.5%) history of hypertension, 4 (6.3%) insulin-dependent diabetes mellitus, 4 (9.7%) chronic renal failure, 2 (3.1%) previous stroke, and 3 (4.7%) previous TIA. A total of 25 patients (39.1%) had a previous MI (⬎ 3 months), 11 (17.2%) a recent MI (⬍ 3 months), and 13 (20.3%) had previously undegone percutaneous transluminal coronary angioplasty (PTCA).
Surgical Indications At our hospital there were two different categories of possible indications for MIDCABG. ELECTIVE INDICATIONS. Candidates for the MIDCABG procedure were considered to be those patients with isolated LAD disease if: (1) a PTCA (with or without stent) was not considered feasible because of technical aspects such as proximal or complex lesions, or total LAD occlusion; (2) a restenosis after a previous PTCA (with or without stent) had occurred; or (3) the cardiologist or the patient asked for the minimally invasive surgical procedure.
0003-4975/00/$20.00 PII S0003-4975(00)01371-0
Ann Thorac Surg 2000;70:456 – 60
NECESSITY INDICATIONS. Candidates for MIDCABG could also be patients with multiple vessel disease if it was felt that the surgical trauma of a standard CABG procedure could increase prohibitively the perioperative risk. Assuming that the LAD lesion had to be suitable for surgery, the other coronary lesions had to show one or more of the following features: (1) occluded and refilled by collateral circulation; (2) going to previously infarcted territories; or (3) not graftable because of technical aspects (eg, distal stenoses with small coronary size, or heavy calcifications).
Surgical Contraindications and Exclusions Contraindications to MIDCABG were the following: (1) a small LAD (internal size ⬍ 1.5 mm); (2) a diffusely calcified LAD; or (3) an intramyocardial LAD. All of these features could be suspected preoperatively by careful preoperative assessment of the coronary angiography before surgery. In our series, 52 patients (81.1%) underwent MIDCABG for elective reasons, namely, because of an isolated lesion of the left anterior descending artery, whereas the remaining 12 patients (18.9%) underwent the procedure for necessity reasons; they were affected by double-vessel (9 patients, 14.1%) or triple-vessel (3 patients, 4.7%) disease.
Surgical Technique Surgical technique was as previously described [1]. Of note, in all of these patients the left internal mammary artery (LIMA) was harvested under direct vision and a special spreader (Autosuture International Inc, Norwalk, CT) was routinely adopted starting from November 1996 (case 30) and used together with a LAD stabilizer.
Angiographic and Doppler Control An echo-Doppler study of LIMA patency was performed within 1 week and every 6 months postoperatively: the LIMA-to-LAD Doppler flow velocity was evaluated using an echo-color Doppler measurement system (Acuson 128 XP10 ART; Acuson Inc, Mountain View, CA), as previously described [2, 3]. Moreover, before discharge all patients underwent a postoperative angiographic reinvestigation of LIMA-to-LAD grafts.
Quality of Life The patients completed two self-administered questionnaires for the evaluation of their quality of life, namely, the Physical Activity Score and the Psychological General Well-being Index. The Physical Activity Score is a part of an anginaspecific questionnaire, the Angina Pectoris Quality of Life Questionnaire, which contains 25 questions. The last nine questions of the Questionnaire cover leisure activity and physical limitations, and the six questions for the self-estimation of physical abilities and limitations are the body of the Physical Activity Score. Each response is graded from 1 to 6, and the average value for all six questions is calculated, with the higher value representing the greater degree of impaired ability [4].
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The Psychological General Well-being Index was initially constructed to measure subjective well-being or distress [5] and has been used for studies in hypertension [6], angina pectoris and cardiac surgery [7–14], menopausal disorders [15], and gastrointestinal diseases [16]. It comprises 22 items that address six different dimensions of the well-being of each patient: anxiety (five items), depressed mood (three items), positive well-being (four items), self-control (three items), vitality (four items), and general health (three items). Every response can be graded from 1 to 6 (total range, 22 to 132), with the greater value corresponding to superior well-being [5]. The wellbeing score can be affected by factors such as sex and gender. In a study performed in a normal, nonselected European population, women tended to have lower scores than men, and patients 30 to 60 years of age had relatively lower scores than younger or older patients [17]. The questionnaires were mailed to all patients before surgery and were returned at the time of hospitalization for MIDCABG. The same questionnaires were then mailed to patients 6 and 12 months after surgery. All of the questionnaires were validated carefully and tested for reliability.
Follow-up Follow-up information, which was available for 100% of the patients, was obtained by direct examination of the patient. The date of the last inquiry was March 1999. The following end points were collected for each patient: (1) survival; (2) acute myocardial infarction-free survival; (3) angina-free survival; (4) redo-free survival; (5) PTCA-free survival; (6) PTCA on LAD-free survival; (7) redo or PTCA-free survival; (8) survival free from any new hospitalization for cardiac causes; (9) survival free of cardiac events (acute myocardial infarction [AMI], redo, PTCA, angina, or hospitalization for cardiac causes).
Statistical Analysis All continuous data are expressed as mean ⫾ SD (when indicated, the median is reported in brackets); categorical variables are reported as percentages. A commercial statistical software package (SPSS for Windows, version 8.0, SPSS Chicago, IL) was used for data analysis. Continuous variables were tested with the nonparametric Mann-Whitney test. Survival rates for the entire patient population were determined by Kaplan-Meier survival analysis, and the estimated survival proportions are reported plus or minus the standard error of the estimates. A statistical probability of less than 0.05 was considered as indicating significance.
Results Early Results All patients underwent MIDCABG through a left anterior thoracotomy; in all cases a LIMA-to-LAD anastomosis was performed on a beating heart; no conversions to sternotomy were performed. The LAD occlusion time was 25.7 ⫾ 7.8 minutes, whereas the anastomosis time was 18.4 ⫾ 6 minutes. The occlusion of the LAD never caused life-
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Table 1. Average Physical Activity Scores Before and After Minimally Invasive Direct Coronary Artery Bypass Grafting
Average score Percent change
Before Surgery
6 Months After Surgery
12 Months After Surgery
4.2 ⫾ 0.9 (4.4)
3.0 ⫾ 1.1 (3.1)a ⫺28.5%
2.9 ⫾ 0.7 (3.1)a ⫺31.0%
Scores are reported as mean ⫾ SD (median in parentheses). a
p ⬍ 0.01 vs before surgery.
Negative percent change values indicate improvement.
threatening ventricular arrhythmias or major hemodynamic changes; in no case was an IABP or emergency CPB needed. Surgery time was 2.3 ⫾ 0.5 hours and the wound length at the end of surgery was 10.5 ⫾ 1.2 cm; in one case only (1.6%) the thoracotomy was enlarged up to 16 cm because of an abnormally lateral LAD. No perioperative deaths occurred. One patient (1.6%) showed perioperative myocardial septal infarction without hemodynamic deterioration and 3 patients (4.7%) underwent reoperation for bleeding. The mean ventilatory support time and the mean ICU stay were 7 ⫾ 6.4 hours and 23 ⫾ 10 hours, respectively. Postoperative length of stay was 5.9 ⫾ 1.5 days.
Graft Patency Studies Predischarge echo-Doppler study of the LIMA showed a severe impairment of flow in 4 patients (6.3%), characterized by a systolic velocity in the LIMA graft of less than 10 cm/s and a loss of the diastolic component. The graft angiography performed in these patients showed occlusion of the LIMA to LAD graft in two cases and a significant (⬎ 70%) anastomotic stricture in the remaining two cases. One of these patients underwent redo CABG with full sternotomy, cardiopulmonary bypass, and cardioplegic arrest, whereas in the remaining 3 patients a percutaneous angioplasty resolved the anastomosis problem. Predischarge MIDCABG angiographic patency rates were 62 of 64 (96.8%) for overall patency and were 60 of 64 (93.8%) for perfect patency of the grafts. Follow-up studies performed every 6 months with the echo-Doppler technique showed the persistence of similar blood flow patterns of the LIMA grafts with respect to the early reinvestigation, with no significant variations in the flow characteristics in any single graft.
Measurement of Quality of Life The Physical Activity Score improved significantly after the operation, with a percentage improvement of 28.5% and 31% at 6 and 12 months, respectively (Table 1). The same behavior was shared by the Psychological General WellBeing Index, which improved 17.9% and 23% at 6 and 12 months, respectively (Table 2); the analysis of the six different subscales of the test revealed significant improvements in anxiety, positive well-being, vitality, and general health (Fig 1).
Follow-up Studies Average follow-up was 25 ⫾ 11.4 months (median, 21). Estimates of overall survival and survival free estimates of cardiac-related events are reported in Table 3. Of note, 3-year survival was 100%, AMI-free survival 98.4% ⫾ 1.6%, and angina-free survival 91.8% ⫾ 4.8%.
Comment Less invasive cardiac surgery is a new and significantly different approach to treat a variety of cardiac surgery procedures, and MIDCABG performed with smaller incisions (usually thoracotomies) and without cardiopulmonary bypass is becoming more and more popular. The reasons for the success of these procedures are shorter hospital stay, rapid recovery, faster return to activity, reduced patient morbidity, and less postoperative pain than with standard procedures [18 –20]. Among the new techniques to treat coronary artery disease, MIDCABG has rapidly become the most popular technique used to revascularize the most important coronary artery (LAD) with the most important arterial conduit (LIMA), which is the strongest predictor for long-term and redo-free survival after surgical myocardial revascularization [21, 22]. The maturation of experience in this field and the continuous improvement in techniques and instruments (especially stabilization devices) have allowed surgeons to perform the LIMA-to-LAD anastomosis on a beating heart through a small thoracotomy in a comfortable and reproducible way [23]. It is now becoming clear that early patency rates for this operation in coronary patients are approaching the patency rates for the same anastomosis performed on bypass and with cardioplegic arrest; in fact, the recent results of
Table 2. Average Total Scores for the Psychological General Well-Being Index Before and After Minimally Invasive Direct Coronary Artery Bypass Grafting Before Surgery Average score Percent change
84.3 ⫾ 10.4 (82.4)
Scores are reported as mean ⫾ SD (median in parentheses). a
p ⬍ 0.01 vs before surgery.
Positive percent change values indicate an improvement.
6 Months After Surgery
12 Months After Surgery
99.4 ⫾ 11.1 (98.8)a 17.9%
104.0 ⫾ 7.9 (105.5)a 23.0%
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Fig 1. Bar graph of the six different domains of the Psychological Well-Being Index (PGWBI) as assessed before and 1 year after minimally invasive coronary artery bypass grafting (*p ⬍ 0.01 1-year follow-up vs preoperative evaluation).
this relatively new technique document overall early patency rates exceeding 95% [23–25]. Previous studies have also shown that conventional coronary bypass surgery procedures significantly improve quality of life in patients soon after surgery [7–9] and that, in patients with multivessel disease, coronary surgery yields a better quality of life than coronary angioplasty. The investigators of the Bypass Angioplasty Revascularization Investigation (BARI) trial [10] documented better improvement in both functional status and emotional health during 3 years of follow-up of patients undergoing CABG for multivessel coronary disease. Furthermore, the quality of life is also improved in subgroups of patients with coronary artery disease presenting with risk factors or comorbidities such as hypertension [11] or diabetes [12], or in octogenarians [13]. However, little information is available on midterm clinical results and especially on quality of life after MIDCABG; to our knowledge, only Calafiore and colleagues [26] reported a 27-month survival of 97.1% ⫾
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0.7% and an event-free survival of 89.4% ⫾ 1.2% after this procedure. The aim of our study was to provide more information about the outcome of patients who undergo this new procedure and, especially, to assess possible improvements in their quality of life. In fact, during the past years, the need to assess how patients feel has developed, and prior evaluations of quality of life by means of surrogate end points such as freedom from angina or of return to work after surgery have become unsatisfactory. For that reason the use of standardized questionnaries has been introduced to assess changes in quality of life in cardiovascular medicine and, especially, therapeutic options for coronary artery disease [4 –14]. This study documents how patients undergoing MIDCABG showed a consistent improvement in their quality of life as assessed by the Physical Activity Score and the Psychological General Well-Being Index, two of the commonly employed batteries of tests to assess changes in quality of life after coronary surgery [11, 12, 14]. Furthermore, the results obtained with MIDCABG seem to compare favorably, in terms both of survival and of event-free survival, with interventional cardiology procedures (PTCA on LAD). In fact, for angioplasty on LAD previous studies document 1- and 3-year survival rates of 97% and 95%, respectively, angina-free survival rates at 1 year of 90% when a stent was used, and of 75% for PTCA without a stent, angina-free survival of 75% at 3 years when using conventional interventional cardiology techniques, and an event-free survival at 1 year of 87% for PTCA with stent and of 70% for PTCA [27, 28]. One of the possible criticisms of this study is that both patients with elective and necessity indications to CABG were assessed together, and this could have affected the possible recurrence of symptoms, the need for new cardiac procedures, or the magnitude of the possible improvements in the quality of life. However, the assessment of the same end points for the patients by indication to surgery (elective vs necessity) could not show any significant difference in event-free survival rates or in the percentage improvement of the tests administered to assess the quality of life (data not shown). The fact that both patients with elective and necessity indications had
Table 3. Survival and Event-Free Survival Rates of Patient Population Variable Patients at risk Survival AMI-free survival Redo-free survival PTCA-free survival PTCA- to LAD–free survival Redo– or PTCA–free survival Angina-free survival New hospitalization–free survival Cardiac event–free survival AMI ⫽ acute myocardial infarction;
1 Year
2 Years
3 Years
64 100% 98.4% ⫾ 1.6% 98.4% ⫾ 1.6% 92.2% ⫾ 3.4% 95.3% ⫾ 2.6% 93.8% ⫾ 3.0% 98.4% ⫾ 1.6% 96.9% ⫾ 2.2% 90.6% ⫾ 3.6%
47 100% 98.4% ⫾ 1.6% 98.4% ⫾ 1.6% 92.2% ⫾ 3.4% 95.3% ⫾ 2.6% 93.8% ⫾ 3.0% 95.2% ⫾ 3.6% 96.6% ⫾ 2.2% 86.9% ⫾ 5.5%
22 100% 98.4% ⫾ 1.6% 98.4% ⫾ 1.6% 92.2% ⫾ 3.4% 95.3% ⫾ 2.6% 93.8% ⫾ 3.0% 91.8% ⫾ 4.8% 96.6% ⫾ 2.2% 86.9% ⫾ 7.5%
LAD ⫽ left anterior descending artery;
PTCA ⫽ percutaneous transluminal coronary angioplasty.
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similar event-free rates and similar percentage improvement in well-being adds further support to the pivotal role of the LIMA to LAD anastomosis in myocardial surgical revascularization. In other words, the strength of this anastomosis seems by far to be most important in determining the fate of patients undergoing CABG. Another limitation of the study is that it did not include a control group, and for this reason it is impossible to determine how much of the change in quality of life was due to this new surgical procedure and how much was due to other factors such as the simple follow-up of the patients. However, it was believed to be unethical to deny the chance for revascularization to a cohort of patients who show their main lesion on the most important coronary vessel and target for revascularization. Additional prospective comparisons of different ways to manage LAD disease (PTCA, conventional CABG, or MIDCABG) will be needed to document possible differences in postoperative outcomes. In conclusion, MIDCABG is an effective way to improve the quality of life and to provide angina relief for selected subgroups of coronary patients. The midterm survival and event-free survival rates achievable with this surgical option are encouraging, even if longer follow-up times are needed for a more precise assessment of the results of this surgery.
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