INTRODUCTION

Scientific and technological advances over the last 20 years have led to considerable changes in the way in which ischemic heart disease patients are diagnosed and treated.1-3 Our center is a tertiary-level hospital which has provided interventional cardiology services since 1985; a registry of procedures performed has been kept since that time.

The objective of the present study was to describe coronary interventions carried out in our center since 1985. We include a description of baseline patient characteristics, the clinical context, the techniques used, and the outcomes obtained. Each of these aspects is analyzed according to the period in which the procedure was performed and by patient age and gender.

METHODS

Procedures

The coronary intervention program was set up in our hospital in 1985. From January 1, 1986 to December 31, 2005, a total of 61 862 diagnostic coronary angiographies (CA) and 17 204 percutaneous transluminal coronary angioplasties (PTCAs) were carried out. These were analyzed for a series of four 5-year periods which constitute the basis of this study. Procedures performed in 2006 were included as a reference though they are not included in the analysis.

Treatment Protocols for the Different Study Periods

There have been considerable changes over the study period in the diagnosis and treatment of patients with acute coronary syndromes. For each of the different study periods, Figure 1 outlines indications for CA and the priority assigned to each diagnostic procedure based on the patient's clinical condition. Until the mid-1990's, the approach to patients with unstable angina or non-Q wave infarction was to clinically stabilize the patient and, once the initial crisis had passed, to selectively perform CA in patients with recurrent angina or evidence of ischemia. From the mid-1990's on, a more invasive strategy was adopted in non-ST segment elevation acute coronary syndromes, with CA being performed systematically and earlier, ie in the first 2-4 days after the event up to year 2000, and in the first 24 hours since then. This was followed by PTCA when indicated. Likewise, until the year 2000, patients with acute myocardial infarction (AMI) and ST segment elevation were generally treated with fibrinolysis and received CA in cases of recurrent ischemia (spontaneous or induced). Immediate PTCA was only performed when fibrinolysis was contraindicated, had failed, if there was hemodynamic compromise, or if there was immediate availability in the hemodynamics unit. From 2001, primary PTCA became the usual reperfusion treatment for patients attending our center, while those attending other reference hospitals were generally treated with fibrinolysis and sent for urgent CA only when fibrinolysis was contra-indicated or had failed; the remaining patients would be sent for elective CA after 24-48 hours.

Figure 1. Time at which coronary angiograph performed according to patient's clinical situation and study period. CA indicates coronary angiograph; PTCA, coronary angioplasty; AMI, acute myocardial infarction.

Data Collection

Data collected prospectively on patients after every PTCA included the presence of risk factors, cardiac history, the clinical indication for the procedure, the technique employed, and the initial outcome. Data on in-hospital events were entered for all patients on discharge and after reviewing discharge or inter-hospital transfer reports, or death certificates. Only variables collected systematically and consistently over the last 20 years are described in this paper. Data on PTCA in AMI were available from 2000 onwards (1708 procedures).

Definition of Variables

­ Smoking: current smoker or smoker within the last 5 years

­ High blood pressure: earlier diagnosis of high blood pressure, or receiving treatment for high blood pressure

­ Diabetes mellitus: earlier diagnosis of diabetes mellitus, or receiving treatment for diabetes

­ Hyperlipidemia: earlier diagnosis of hyperlipidemia or receiving lipid-lowering treatment

­ Stable angina: pattern of stable angina of > 1 month duration

­ Silent ischemia: ischemia determined by electrocardiographic or imaging techniques. Angina not present

­ Unstable angina: newly appearing angina, progressive, resting, or prolonged in the month prior to PTCA without positive necrosis markers

­ Non-Q wave AMI: prolonged pain accompanied by electrocardiographic changes and positive markers (creatine kinase [CK] or creatine kinase MB isoenzyme [CK-MB] to 1998, and troponin I since that time)

­ AMI with elevated ST segment: PTCA (primary or rescue) performed within 12 h of onset of clinical event.

­ Elective PTCA: not high priority; urgent PTCA: 24-48 hours; emergent: performed immediately

­ Multi-vessel angioplasty: lesions treated in more than one of the 3 major epicardial arteries

­ Angiographic success: residual stenosis in <30% of the treated vessel

­ Major complication: death, infarction (2-fold elevation of CK or CK-MB), repeated revascularization of the same vessel, surgery required

Statistical Analysis

Continuous variables were expressed as means (standard deviations). Categorical variables were expressed as numbers and percentages. Variables were analyzed according to the period in which the procedure was performed, gender, and age group (< or ≥75 years) for each period. Student t test was used to compare between normally distributed continuous variables, a test of medians was used to compare variables with a non-normal distribution, and ANOVA was used to test for change over time. Categorical variables were compared using χ2 and change over time was assessed using a test for linear trend. A P-value less than .05 was considered significant. Statistical analysis was performed in SPSS version 13.0.

RESULTS

Of the 17 204 PTCAs performed, 20% (3500) were carried out in women and 17% (2834) in patients over 75 years of age. The number of procedures by period, sex, and age is shown in Figure 2. The proportion of women receiving the intervention increased considerably and the proportion of patients aged 75 years or over tripled. Figure 3 shows the increase in mean age in patients of both sexes for the different study periods. Figure 4 shows the classic risk factors by age, sex, and period; Figure 5 shows prior cardiac history and Figure 6 shows the clinical indication for PTCA. Table 1 shows the PTCA priority rating, the type of vessel treated, the technique used, the immediate outcome, and in-hospital events over the different study periods by gender. Table 2 provides data on the same variables for the 2 age groups, and Table 3 details the procedures performed in 2006. Figure 7 shows the change over time in the number of procedures performed immediately following AMI (first 12 hours from onset), distribution by sex and age, and the percentage of total PTCAs. Table 4 details the procedures performed immediately following AMI over the period 2001-2005.

Figure 2. Number of angioplasties by study period, gender, and age group. Percentages are provided in the Table below the Figure.

Figure 3. Mean age at angioplasty by gender. *P-value for comparison by gender.

Figure 4. Risk factors by gender and study period in patients receiving an angioplasty. HBP indicates high blood pressure.

Figure 5. Cardiac history prior to the current indication for coronary angioplasty, by gender and study period. PTCA indicates percutaneous transluminal coronary angioplasty; AMI, acute myocardial infarction.

Figure 6. Clinical indication for angioplasty by gender and study period.

Figure 7. Number of procedures performed with acute myocardial infarction (AMI) in the last 10 years, percentage of women and those over 75 years. The table underneath details the percentage of angioplasties in AMI in relation to the total number of coronary angioplasties (PTCA).

DISCUSSION

The number of PCI procedures has increased considerably in Spain in recent years.4

The stabilization in the number of diagnostic catheterizations was accompanied by a 5% annual increase in the number of therapeutic procedures in our center stemming from broader indications for the intervention (more acute infarcts, more older patients). Patients receiving PTCA are increasingly older in Spain and in other countries.5,6 In the series reported here, the increase in age was similar in men and women over time, which meant that the difference between them remained constant. Although the proportion of women receiving the interventions increased, it was still lower than the 34% reported in the US registry.6 Given the ageing of the population and the predominance of women among older age groups, this trend can be expected to continue in coming years.

In terms of risk factors, smoking decreased in men but not in women. From the first period on, high blood pressure, diabetes, and dyslipidemia were more frequent in women, and remained so in later periods. There was an increase in risk factors among men in later periods.

A prior history of AMI was more frequent in men in all of the periods analyzed, and a trend towards an increase over time in both sexes. The same was true regarding prior PTCA, which was observed in 25% of men and 22% of women in the last 5-year period. These figures were lower than the 32% reported for the US registry. Prior surgery was infrequent in both men and women, and was stable at around 7% in men and 5% in women. These proportions were also lower than those observed in the European5 and US6 registries.

Regarding indications for procedures at our center, acute coronary syndromes consistently predominated, both in men and women, with percentages of 70% in the last 5 year period. This is considerably higher than the corresponding percentages in the European Heart Survey (46%)7,8 and the US registry(62%),6 and remained stable over the period. Ad hoc procedures were increasingly frequent in men and women in all age groups, and accounted for 65% of all procedures in the last study period. This is slightly lower than figures published for other centers and can be attributed to logistic factors and to a policy of joint decision-making with specialist clinicians when doubt exists. The number of urgent and immediate procedures also increased over successive study periods and was slightly higher in women and older patients in all study periods.

Both the number of lesions treated and the number of multi-vessel procedures increased slightly but consistently over the entire study period in men and women, and in both age groups. In the series as a whole, only 12% of all procedures were multi-vessel, with a mean of 1.3 lesions treated per procedure.

Vessels treated were smaller in women; in the series as a whole, 34% of dilated vessels were under 3 mm in women compared to 22% in men. Vessels treated also tended to be smaller in older patients, in part at least because of the greater prevalence of women in this group. Dilatation of non-native (saphenous and mammary) vessels accounted for under 2% of the total number of angioplasties in all periods, in both sexes and in both age groups.

Rotational atherectomy was only used in a small proportion of patients. In the last 10 years, it was used in 1%-2% of procedures, with a slight increase (to 3%) in 2006. There was no difference in its rate of use by gender, though it was used slightly more often in older patients. The number of procedures employing stents increased rapidly in the second half of the 1990s and accounted for over 90% of procedures in 2000, and 94% in 2006. The number of stents per procedure and the length of the stents also increased; the increase was similar in men and women and in the 2 age groups. The percentage of interventions employing drug-eluting stents also increased from their first use in 2001 to 63% in 2006. Drug-eluting stents were used more frequently in women than men because of the higher prevalence of diabetes and small-caliber blood vessels. This type of stent is used systematically in our center in both of these circumstances.

Outcomes of PTCA have improved over time, from an 87% success rate in the first period to 93% in the last. Over the first three 5-year periods, success rates in women were slightly lower, but differences decreased to the extent that no significant differences were observed between men and women in the last year. As observed in other series,9 in-hospital mortality is still significantly higher in women, even in elective procedures, although there is a tendency toward a reduction in the differences between men and women in PTCA-related mortality. The success rate was also slightly lower in older patients, and rates of complications were higher. Hospital mortality rates were higher in patients over 75 years of age. The number of procedures performed during AMI has increased substantially, from 3% of the total number of PTCAs carried out in 1996 to 17% in 2006. Both male and female patients receiving the procedure with an AMI were somewhat younger (about 2 years) than those in the overall series, but there were no differences in terms of risk factors. The only exception to this was the presence of diabetes, which was more frequent in women in the series as a whole (38%) compared to those receiving PTCA with AMI (28%). This difference was not seen in male patients (20% in the overall series compared to 19% in the AMI patients). No differences were observed between men and women in terms of prior history (although there was a trend towards a greater frequency of prior PTCA in men), nor in infarct site.

A higher rate of rescue angioplasties was observed in males and there was a longer delay for both primary11,12 and rescue13 PTCAs in women, with a difference of 80 min between sexes for both types of procedure. As described elsewhere,14-16 cardiogenic shock was more frequent in women. Stents were implanted in a similar number of procedures (92% in both sexes) and angiographic success was achieved in 94%, with no differences by gender. However, 30 day mortality was greater in women,17-19 in part because of a higher frequency of cardiogenic shock, although the difference was maintained even when cases of cardiogenic shock were excluded from the analysis (8% vs 3.4% mortality, respectively, for women and men).

CONCLUSIONS

Significant changes were observed over the last 20 years in the baseline characteristics of, the techniques used in, and the outcomes obtained in patients undergoing percutaneous coronary intervention. The data provided complement those provided by the hemodynamics unit registry and help to characterize the changes that have taken place over the last 20 years.

AKNOWLEDGEMENTS

We would like to express our thanks to doctors Andrés Iñiguez, Javier Segovia, Javier Goicolea, Manel Sabaté, and Raúl Moreno, who performed a considerable number of the procedures described in this study while they were with our unit. To the fellows and resident doctors who have helped to maintain the quantity and quality of the information container in our database.

ABBREVIATIONS
AMI: acute myocardial infarction
CA: coronary angiography
HBP: high blood pressure
PTCA: percutaneous transluminal coronary angioplasty

Correspondence: Dra. R. Hernández-Antolín.
Unidad de Hemodinámica. Instituto Cardiovascular.
Hospital Clínico San Carlos.
Martín Lagos, s/n. 28040 Madrid. España.
E-mail: rhernandez_antolin@hotmail.com

Received August 8, 2006.
Acepted for publication May 21, 2007.