Kennard, Elizabeth D.
The New Approaches to Coronary Intervention (NACI) Registry was funded by the National Heart, Lung, and Blood Institute (NHLBI) to document the safety, efficacy, and modes of use of seven new interventional devices used for the treatment of coronary artery disease. The history and methods of the registry have been previously described. 1 The new interventional devices were developed to circumvent problems experienced with balloon angioplasty. The first of these was that certain lesion subsets were not susceptible to treatment. For example, the balloon catheter often could not cross a completely occluded vessel, and the laser catheter was developed to open up the stenosis sufficiently to allow the balloon to be used. 2 Another problem was the occurrence of acute closure of the artery after balloon angioplasty, often the result of a dissection, which frequently necessitated the use of bypass surgery. 3 Metal stents designed to act as a scaffold to the artery were developed to avert acute closure and the need for bypass surgery. 4 Stents also proved to be efficacious in reducing the rate of restenosis after angioplasty, as was demonstrated by the STRESS (Stent Restenosis Study) 5 and Belgian Netherlands stent (BENESTENT) trial. 6
Several studies have reported less success with balloon angioplasty 7,8 in women, and also with new-device angioplasty in women. 9,10 This has been attributed to the presence of more coronary disease risk factors in women, the size and characteristics of the coronary arteries in women, or the differing stages of disease found in women presenting for treatment. Most of these studies, however, did not distinguish between the different modes of device use, or limited the study to one particular mode of use. 11
This report describes differences in baseline characteristics, lesion characteristics, and acute and long-term outcome in men and women treated with new devices in both planned and unplanned modes.
Subjects and Methods
Between August 1990 and March 1994, 4,423 patients were enrolled into the NACI Registry; 1,542 were women and 2,881 were men. This included 528 women whose recruitment was made possible by supplemental funds from the Office of Research on Women’s Health. In the NACI Registry, the mode of use of each device was described in detail. 12 A planned use of the device was defined as use as a definitive treatment for a lesion either as a single device, after another device, or before another device. Unplanned use was defined as use for a suboptimal result after another device, for previous device failure, for abrupt closure after other device use, or for treatment of a device-induced complication in another segment. An angiographic core laboratory analyzed 89% of the angiograms for the initial procedures and provided preprocedure, postdevice, and postprocedure measurements of vessel and lesion dimensions. 13 The core laboratory also recorded morphology after each device intervention. All angiographic and morphology measurements in this report refer to the angiographic core laboratory analyses.
There were 1,561 patients enrolled in the NACI Registry who had no prior revascularization, were treated with a single new device [or a new device and percutaneous transluminal coronary angioplasty (PTCA)], and had core laboratory readings available. Of these, 840 were men and 721 were women. Because the recruitment was enriched with additional women, these numbers should not be interpreted as representative of the distribution of device use in men and women (Figure 1).
Table 1 shows the devices used and the mode of device use for both men and women. Women were more likely than men to receive treatment with the Rotablator device (Boston Scientific, Boston, MA) and less likely to receive treatment with the Palmaz-Schatz stent. Planned use accounted for 78.9% of the device attempts in the men and 82.3% in the women. A substantial proportion of the planned attempts occurred before the use of other devices (PTCA), reflecting the use of the new devices for opening up a difficult lesion for subsequent treatment. A small proportion of device attempts occurred after the use of other devices (PTCA).
The majority of unplanned use occurred after suboptimal results had been obtained using another device (PTCA), or after the PTCA had failed. Correction of abrupt closure of the vessel was the reason for use in only 2.8% of women and 3.5% of men. Unplanned new-device use was mostly with the Palmaz-Schatz stent or the Gianturco-Roubin stent.
The baseline characteristics of men and women for both modes of treatment are shown in Table 2. For planned treatment, women were older than men by about 5 years (mean age 65.7 years for women vs 60.6 years for men, P < 0.001). Women also were more likely to have congestive heart failure (14.5%vs 8.3%, P < 0.001), diabetes (25.1%vs 16.4%, P < 0.001), hypertension (64.4%vs 46.2%, P < 0.001), and unstable angina (70.9%vs 50.5%, P < 0.001). The women were also at higher risk for bypass surgery (10.3%vs 4.9%, P < 0.001). There were no significant differences in prior myocardial infarction, duration of pain, or number of diseased vessels.
Similar differences were noted for patients undergoing unplanned new-device use, although the differences were smaller. The proportion of patients with prior myocardial infarction was much higher in the unplanned group, for both men and women, reflecting the higher proportion of people in this group who were actually being treated for this indication.
The preprocedure characteristics of those lesions treated with a new device are described in Table 3. For planned attempts, women were significantly more likely than men to have a treated lesion in the right coronary artery (43.8% of lesions vs 28.1% for men, P < 0.001). Lesions in an ostial location were also more frequent for the women (27.1%vs 19.2%, P < 0.001). Other lesion characteristics were comparable between men and women. However, for planned attempts, the frequencies of adverse characteristics such as class C lesions, calcified lesions, and total occlusions were high. Unplanned lesion characteristics were similar for men and women. Unplanned lesions were more likely to be totally occluded than were the planned lesions.
Quantitative angiography of the new device-treated lesions as determined by the angiographic core laboratory is shown in Table 4. Women had smaller arteries than men for both planned and unplanned attempts, and the preprocedure mean percentage stenosis was lower. After the procedure, men and women achieved an equal reduction in stenosis in the planned treatments (26% residual stenosis for both groups). Unplanned treatment, however, resulted in a lower residual stenosis for the women than for the men (20%vs 25%, P < 0.05). Angiographic success was defined as a residual stenosis of less than 50% and a change of stenosis of at least 20%. By this definition a high level of success was achieved in both planned and unplanned treatment, with no significant differences between the women and the men. However, for unplanned treatment, women were significantly more likely than men to achieve success (97%vs 89%, P < 0.01).
For unplanned use of the new devices, the lesion characteristics that were present immediately before the placement of the new device, that is, after the failed or suboptimal attempt, are shown in Table 5. Dissection was very frequent. Women had dissections (NHLBI dissection grade 14 B or above) in more than 87% of cases, and the men in 70% of cases. Of these dissections, approximately 16% of women and 18% of men had flow-limiting grades E and F. Thrombolysis in Myocardial Infarction trial (TIMI) 15 grade 0/1 was noted in 17% of each group, indicating those patients with no or very little flow after the previous PTCA attempt. The mean area stenosis for each group post-PTCA was more than 50%, which is usually defined as a device failure. Abrupt closure was noted in 21.4% of men and 20.2% of women, and threatened closure in 9.0% of men and 4.3% of women.
Despite these poor lesion characteristics before the use of the new device, the procedural outcome was not very different for the planned and unplanned groups of men and women. Table 6 summarizes the acute (in-hospital) major adverse events and overall procedural success (defined as angiographic success in each new device-treated lesion with no death, Q-wave myocardial infarction, or emergency bypass surgery). For both men and women there were more adverse events after an unplanned new-device attempt, as compared with a planned attempt. Women, however, showed less difference. The overall rate of major events [death, Q-wave myocardial infarction (MI), or emergency coronary artery bypass grafting (CABG)] after unplanned intervention in women was 5.5% compared with 3.7% after planned intervention. For men, the rate of major events after unplanned intervention was 11.7%, more than three times the frequency after planned events (3.5%). A procedural success was defined as angiographic success in all new device-treated lesions with no death, Q-wave MI, or emergency CABG. For planned interventions, the men and women showed similar procedural success rates of 86.5% and 85.2%, respectively. For the unplanned procedures, the men had a procedure success rate of 79.0%, much less than the 90.2% rate obtained for the women.
Table 7 shows the proportion of patients experiencing adverse events in the first year after the subject intervention. Women with either planned or unplanned attempts were less likely to undergo repeat PTCA than were their male counterparts. The combined endpoint of death, Q-wave MI, and target vessel revascularization was also less likely among women than men with either planned or unplanned attempts.
The planned and unplanned modes of new-device use represent two quite different situations. In the first mode, the device is being used in circumstances for which it has been designed, to treat a lesion with characteristics not generally amenable to the more conventional PTCA. In the second mode, a failure, or a suboptimal result, has already occurred, and the new device is used to avoid the necessity for more serious interventions such as bypass surgery. In the planned device attempts in this study, lesions had a high frequency of characteristics generally associated with a lower rate of PTCA success; they were eccentric, calcified, and ostial in location. For the unplanned attempts, lesion characteristics confirm the suboptimal or failure mode, as evidenced by the higher proportion of Class C lesions and complete occlusions. The lesion characteristics that were present immediately before the unplanned new-device use (that is, after the initial PTCA attempt) show a high incidence of dissection and complete occlusion, and stenoses that had not been reduced below the 50% level. Women had a higher frequency of these dissections after PTCA with only 12.8% of the lesions free of dissection before the new-device attempt, vs 30.1% in the men. Despite these unfavorable lesion characteristics, the in-hospital outcomes were excellent. For women, the procedural success was 85% for the planned attempts and 90% for the unplanned attempts. Men had a slightly lower success rate of 79% with unplanned attempts vs 86.5% for planned attempts. This lower success rate for men was due to a higher rate of angiographic failure, as well as higher incidence of both emergency CABG and Q-wave myocardial infarction, compared with both women with unplanned attempts and men with planned attempts. This difference between men and women with unplanned attempts was still present at 1 year, which is due to a much higher frequency of repeat PTCA for the men as well as a higher frequency of serious cardiac events (CABG and Q-wave myocardial infarction).
In summary, women fared equally well whether they had a planned or an unplanned new-device attempt. Success rates were high, and rates of cardiac events were comparable. In contrast, for men the outcome was worse for those with unplanned attempts, both acutely and in the long term.
Following are the conclusions drawn from this study. (1) Men and women had similar rates of unplanned treatment with new devices. (2) Women had more risk factors than men, had a different distribution of treated lesions, and more frequently had a dissection before unplanned stenting. (3) In-hospital outcomes were similar for men and women with planned attempts, but better for women with unplanned treatment; 1-year outcome was also slightly better for women, with a lower rate of repeat revascularization after both planned and unplanned attempts.
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