Complications prior to revascularization among patients waiting for coronary artery bypass grafting and percutaneous transluminal coronary angioplasty.
European Heart Journal (1996) 17, 1846-1851
Complications prior to revascularization among patients waiting for coronary artery bypass grafting and percutaneous transluminal coronary angioplasty A. Bengtson, T. Karlsson, A. Hjalmarson and J. Herlitz The Division of Cardiology and the Wallenberg Laboratory, Department of Heart and Lung Diseases, Sahlgrenska University Hospital, Goteborg, Sweden
patients with a low ejection fraction and among patients with a history of diabetes mellitus. In all, 29% required hospitalization prior to the procedure. The most common reason was symptoms of angina pectoris requiring hospitalization in 23% of the patients.
Patients and methods All the patients on the waiting list for possible coronary revascularization in September 1990 in western Sweden.
Conclusion Among patients on the waiting list before either coronary artery bypass grafting or percutaneous transluminal coronary angioplasty, 15 (21%) died prior to the procedure and 1-7% developed a non-fatal acute myocardial infarction. The risk of either death or developing an acute myocardial infarction was highest among patients in the older age groups, among patients with a history of diabetes mellitus and among patients with a lower ejection fraction. (Eur Heart J 1996; 17: 1846-1851)
Results Of 718 patients waiting for either coronary artery bypass grafting or percutaneous transluminal coronary angioplasty, 15 (21%) died between the actual week in September 1990 and prior to revascularization and 12 (1-7%) developed a non-fatal acute myocardial infarction during the same period. All 15 patients who died before undergoing revascularization died a cardiac death. Death and/or the development of an acute myocardial infarction was significantly more frequent among the elderly, among
Introduction A growing number of patients with symptomatic heart disease have required evaluation during the past 2 decades. However, while this group of patients and evaluation for possible revascularization have increased, resources have not kept pace with demand. One of the main problems has been the consequences of the long waiting time for each treatment. This could lead to a new myocardial infarction, sick leave, a higher level of medication and so on, with all their additional costs. With these facts at hand, we initiated a study comprising all the patients on the waiting list for possible coronary revascularization during a week in September 1990. The patients had Revision submitted 19 April 1996. and accepted 29 April 1996. Correspondence: A. Bengtson. The Division of Cardiology and Wallenberg Laboratory. Department of Heart and Lung Diseases. Sahlgrenska University Hospital. Goteborg. Sweden. 0195-668X/96/1211846+06 S25 00/0
Key Words: Coronary revascularization, acute myocardial infarction, waiting list, mortality, hospitalization.
previously been described in terms of their clinical history, quality of life, working situation, medication, chest pain, other cardiac symptoms and waiting time'121. This paper aims to describe the risk of these patients either from dying or developing various complications during the interval between being put on the waiting list and the revascularization procedure.
Patients and methods The patient population consisted of all the patients on the waiting list for coronary angiography, coronary artery bypass grafting and percutaneous transluminal coronary angioplasty in south-western Sweden in September 1990. Almost all the patients had chronic stable angina pectoris and had been referred for an elective procedure'31. A total of 904 patients were sent a questionnaire; 522 patients were on the waiting list for coronary angiography, 325 for coronary artery bypass © 1996 The European Society of Cardiology
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Aim To describe the occurrence of death, development of acute myocardial infarction and need for hospitalization among patients on the waiting list for coronary artery bypass grafting and percutaneous transluminal coronary angioplasty.
Complications prior to revascularization 1847
Table 1 The waiting list All patients
Actual waitinglist patients
Patients remaining on waiting list until revascularization
Number of patients
904
883
718
Age: years, median (range)
63 (24-82)
63 (24-82)
63 (29-82)
714 (79%)
698 (79%)
581 (81%)
21 patients excluded due to administration error
165 patients excluded due to subsequent removal from waiting list
Males
luminal diameter in any of the following arteries or their major branches: left main, left anterior descending, left circumflex and right coronary artery. To classify the number of diseased vessels, a left main coronary stenosis was regarded as equivalent to stenosis in both the left anterior descending artery and the circumflex artery. The left ventricular ejection fraction was estimated from a contrast ventriculogram in the right anterior oblique projection. If no ventricular injection was given, the evaluation was made from an echocardiogram (M-mode) if one had been performed.
Statistics Fisher's permutation test, including Fisher's exact test for dichotomous variables, was used to test for associations with death/acute myocardial infarction. Twosided .P-values were used and are given in the tables if they are below 005.
Results Ninety-one percent of the patients reported a history of angina pectoris, 58% had had a previous myocardial infarction and 46% of the patients had hypertension. The median age of all the patients was 63 years and 81% of them were men. Almost all the patients were limited in their daily activities because of chest pain (91%). Of the patients, 83% were in Canadian Cardiovascular Society classes III or IV and 12% in class II.
The waiting list After exclusions, the study comprised 718 patients (Table 1). Of the original 904 patients, 21 were excluded due to revascularization, removal from the waiting list or death prior to the study week in September, but they were still on the waiting list because of administration errors. Of the 165 who were removed from the waiting list after September 1990 before or after coronary Eur Heart J, Vol. 17, December 1996
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grafting and 57 for percutaneous transluminal coronary angioplasty. A total of 831 patients (92%) answered the questionnaire. In the questionnaire, the following issues were raised: whether the patients had suffered from an acute myocardial infarction, angina pectoris, hypertension, diabetes mellitus, or nervous disorders; their present medication; waiting time for a given procedure; their present working situation; frequency of chest pain, dyspnoea and tachycardia; influence of symptoms on their daily activities; nervous reactions in daily life and sleeping disorders; and their use of sedatives and sleeping pills. The hospital records at each hospital were carefully studied regarding hospitalization, the waiting time, acute myocardial infarction and death before revascularization. If a patient is hospitalized in a hospital other than his/her 'home hospital', information normally reaches the home hospital within a few weeks. For the diagnosis of a confirmed acute myocardial infarction, two of the following criteria had to be fulfilled: (1) chest pain with a duration of at least 15 min; (2) serum enzyme activity of aspartate aminotransferase above the normal range in samples from at least two different days, together with an elevation in serum creatinine kinase. Isoenzymes of creatinine kinase were also measured and in doubtful cases taken into consideration; (3) development of q waves in at least two leads on a 12-lead standard electrocardiogram. Information on death was obtained from the Swedish National Registry of Death. The diagnoses and hospitalization periods were evaluated from the hospital records and thereby the occurrence of acute myocardial infarction during the waiting time. This evaluation included not only the original hospitals but also all the hospitals to which the patients were admitted during the follow-up. The questionnaire asked about current medication. To check the validity of the patients' information, 200 hospital records were checked and found to provide similar information in 98%. The angiographic results were defined according to whether there was a reduction of 50% or more in
1848 A. Bengtson et al.
Table 2
Waiting time (months) Coronary artery bypass grafting (n=435)»
Percutaneous transluminal coronary angioplasty (n = 93)*
11 (0-32)
7 (0-20)
8 (0-33)
6 (0-14)
17 (0-40)
12 (0-34)
From registration to coronary angiography: median (range) From coronary angiography to revasculanzation' median (range) From registration to revascularization: median (range)
*Date of registration missing for 168 coronary artery bypass grafting patients and seven percutaneous transluminal coronary angioplasty patients.
Patient characteristics In Table 3, the patients who underwent either coronary artery bypass grafting or percutaneous transluminal coronary angioplasty are described in terms of distribution of age and sex, previous history of cardiovascular disease, nervous disorders, smoking and findings at coronary angiography.
Medication Waiting time As Table 2 shows, the median total waiting times were 17 and 12 months for coronary artery bypass grafting and percutaneous transluminal coronary angioplasty, respectively, including the waiting time for coronary angiography.
In terms of medication, 74% used two or three of the following: beta-blockers, calcium antagonists and nitrates. Beta-blockers were used by 72% of the patients, long- and short-acting nitrates by 74% and calcium antagonists by 47% of the patients (Table 4).
Death and/or acute myocardial infarction before revascularization (Tables 5 and 6) Table 3 Patient characteristics (n=718) Age; years, median (range) Men Women Previous acute myocardial infarction (58)* Angina pectoris (58) Hypertension (58) Diabetes mellitus (58) Nervous disorders (58) Smokers (57) I -vessel disease (27) 2-vessel disease (27) 3-vesseI disease (27) Main stem stenosis (27) Ejection fraction (152) 60%
In all, 15 patients (21%) died between the actual week in September 1990 and prior to revascularization and a 63 (29-82) 581 (81%) 137 (19%) 386 598 306 76 92 118 116 211 364 75
(58%) (91%) (46%) (12%) (14%) (18%) (17%) (31%) (53%) (11%)
29 (5%) 125 (22%) 412 (73%)
*Figures within parentheses indicate the number of patients for whom information is missing. Eur Heart J, Vol. 17, December 1996
Table 4 Medication (n=666)i Beta-blockers Calcium antagonists Long- and short-acting nitrates ACE inhibitors Salicylates Antihyperlipidaemics Diuretics (for heart failure) Antidiuretics Sedatives (including sleeping pills) No. of anti-ischaemic medications used|: 0 1 2 3 *lnformation missing for 52 of the 718 patients. tBeta-blockers. calcium antagonists and nitrates.
479 310 490 52 407 69 169 46 77
(72%) (47%) (74%) (8%) (61%) (10%) (25%) (7%) (12%)
63 (9%) 111 (17%) 308 (46%) 184 (28%)
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angioplasty, 14 had severe multiple diseases, 20 had satisfactory medical treatment, 25 were inoperable, 25 were not studied due to lack of angina pectoris, 48 were removed due to lack of vessel changes or only minor changes without any significant stenoses, 27 declined surgery, and six had valvular insufficiency. Of the remaining patients, 603 subsequently underwent coronary artery bypass grafting and 100 underwent percutaneous transluminal coronary angioplasty, while 15 patients died before revascularization.
Complications prior to revascularization 1849
Table 5 Death or/and development of acute myocardial infarction in relation to patient characteristics P
6/256 10/316 10/146 21/581 5/137
(2-3%) (3-2%) (6-8%) (3-6%) (3-6%)
13/386 9/274
(3 4%) (3-3%)
18/598 4/62
(3-0%) 6-5%)
13/306 9/354
(4-2%) (2-5%)
7/76 15/584
(9-2%) (2-6%)
2/92 20/568
(2-2%) (3-5%)
3/118 19/543 2/116 5/211 13/364
(2-5%) (3-5%) (1-7%) (2-4%) (3-6%)
3/75 17/616
(4-0%) (2-7%)
2/29 6/125 8/412
(6-9%) (4-8%) (1-9%)
0002
The proportion of patients requiring hospitalization for various reasons during the waiting time is shown in Table 7. In all, 29% required hospitalization. The most common reason was symptoms of angina pectoris requiring hospitalization in 23% of the patients. The median duration of hospitalization was 7 days.
Discussion
0008
003
total of 12 patients (1-7%) developed a non-fatal acute myocardial infarction. All 15 patients who died before undergoing revascularization died a cardiac death. Fourteen of them were autopsied and it was found that 13 patients died of an acute myocardial infarction and one of acute heart failure. One patient died a sudden death in the ambulance. He had a previous history of severe heart disease. One of the patients who developed a non-fatal acute myocardial infarction suffered a fatal myocardial infarction 7 months later, thus reducing the number of patients with end-points to 26.
Univariate analysis Death and/or the development of an acute myocardial infarction was more frequent among the elderly, among patients with a lower ejection fraction and among patients with a history of diabetes. Patients on chronic treatment with antidiabetic drugs and diuretics had a higher complication rate than those who were not.
This study describes the outcome for patients on the waiting list for possible coronary revascularization. The resources in terms of knowledge, medical and technical equipment and treatment have led to an increase in the number of such patients, but without a corresponding augmentation in economic resources . This situation has created long waiting lists. The median total waiting time for coronary artery bypass grafting was almost 15 years and 1 year for percutaneous transluminal coronary angioplasty — very unsatisfactory figures. The long waiting time for coronary artery bypass grafting or percutaneous transluminal coronary angioplasty causes a great deal of negative mental stress for these seriously ill patients, especially in terms of uncertainty about their future'51. In addition, most have suffered from their heart diseases for a long time before being put on the waiting list for surgery. Forty-eight patients were removed from the waiting list because the coronary angiography revealed only small or no vessel changes. Many of these patients were later given the diagnosis syndrome X. Twenty-five patients were in such poor condition, perhaps as a result of the protracted wait, that any operation was hazardous. A shorter waiting time might have resulted in operability in many of these cases. When it came to those who died in conjunction with the operation, the possibility remains that their postoperative complications might have been less serious if the waiting time had been shorter. At this time, there was a public debate in Sweden about medical ethics. The debate was somewhat negative and caused 27 patients to decline any further treatment. The coronary angiography results showed that the majority of patients had severe coronary artery disease and should have had treatment at a much earlier stage. The long waiting time in a state of uncertainty may have added to the disease severity. Of the 718 patients, 15 died while on the waiting list. In all but one of them an autopsy was performed revealing that cardiac disease was the cause of death. Earlier treatment might have minimized the risk of early death and/or a new infarction. In all, 2-1% died prior to revascularization and 17% developed a non-fatal acute myocardial infarction. Few previous studies have evaluated the complication rate among patients on the waiting list. However, Eur Heart J, Vol. 17, December 1996
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Age; years 70 Men Women Previous acute myocardial infarction Yes No Angina Pectoris Yes No Hypertension Yes No Diabetes mellitus Yes No Nervous disorders Yes No Smokers Yes No 1-vessel disease 2-vessel disease 3-vessel disease Main stem lesion Yes No Ejection fraction 60%
Hospitalization between registration and intervention or death
1850 A. Bengtson et al.
Table 6 Death and/or development of acute myocardial infarction in relation to medication before revascularization P Beta-blockers Calcium antagonists Long- and short-acting nitrates ACE inhibitors Salicylates Antihyperlipidaemics Diuretics (for heart failure) Antidiabetics Sedatives (including sleeping pills
13/479 9/187 13/310 9/356 17/490 5/176 4/52 18/614 11/407 11/259 0/69 22/597 11/169 11/497 5/46 17/620 1/77 21/589
2/63 4/111 9/308 7/184
(3-2%) (3-6%) (2-9%) (3-8%)
(2-7%) (4 8%) (4 2%) (2-5%) (3-5%) (2-8%) (7 7%) (2-9%) (2-7%) (4 2%) (0%) (3-7%) (6-5%) (2 2%) (10-9%) (2 7%) (1-3%) (3-6%)
0-01 001
*Beta-blockers, calcium antagonists and nitrates
Mogensen et al. reported a prior-to-procedure death rate of 5-2% among patients referred for cardiac catheterization, 3-8% for patients referred for aortic valve disease and 2-6% for patients referred for coronary artery bypass grafting'61. Naylor et a/.'71 reported that 0-4% of the patients died while on the waiting list181. Death and/or the development of an acute myocardial infarction was more common among elderly patients and patients with diabetes mellitus and a low ejection fraction. This is not an unexpected observation. Table 7 Hospitalization between registration and intervention or death (n = 718)
Total Angina pectoris Acute myocardial infarction Chest pain TIA
Cerebral insult Gastritis Heart failure Arrhythmia Claudicatio intermittens Other
208 162 26 11 1 3 6 7 2 1 31
%t
DaysJ median
29 23 4 2 01 0-4 0-8 1 0-3 01 4
7 6 9 3 8 6 5 8 5-5 17 7
*Number of patients requiring hospitalization tPercentage of patients requiring hospitalization. JMedian number of days in hospital among patients who were hospitalized. TIA=Transitory ischaemic attack. Eur Heart J, Vol. 17. December 1996
In fact, old age as well as a history of diabetes and low ejection fraction have been shown to be important predictors of a worse prognosis among patients with other manifestations of ischaemic heart disease'9""1. Other studies have found unstable angina pectoris, cardiac enlargement, a positive exercise test
