Correspondence

A Comparison of Coronary-Artery Stenting with Angioplasty

N Engl J Med 1997; 337:277-278July 24, 1997

Article

To the Editor:

The article by Versaci et al. (March 20 issue)1 reports more favorable clinical and angiographic outcomes for the treatment of isolated primary stenosis of the proximal left anterior descending coronary artery with stenting than with balloon angioplasty. The main advantage of stenting was a much lower rate of recurrence of angina during the follow-up period. However, the authors fail to inform the reader how this was assessed. Was the clinical evaluation carried out by physicians and nurses who were unaware of whether the patients had undergone balloon angioplasty or stenting? The authors claim that the angiograms were analyzed by two observers who were blinded to the treatment assignments, but Palmaz–Schatz stents (Johnson & Johnson Interventional Systems, Warren, N.J.), which were used, are visible on angiograms.

More important, after the procedure and at follow-up, the mean reference diameter of the left anterior descending coronary arteries treated with balloon angioplasty was only 0.1 mm smaller than that of the arteries treated with stenting (3.2 vs. 3.3 mm). Since the base-line reference diameters were the same, there is a marked difference in the balloon:artery ratios in the two groups (<1.0 in the balloon-angioplasty group, as compared with 1.06 in the stenting group). In addition, the maximal balloon-inflation pressure used was much lower in the patients who underwent balloon angioplasty than in those who received stents (6.0 vs. 10.1 atm).

Although we do not know whether compliant or noncompliant balloons were used in this study, it is obvious that larger balloons and higher pressures were used to implant stents than to carry out balloon angioplasty. Could these differences account for the smaller gain in minimal luminal diameter (0.6 mm less in the balloon-angioplasty group than in the stenting group) and the higher rates of angiographic and clinical restenosis in the patients who underwent balloon angioplasty? The immediate gain in the minimal luminal diameter is the strongest predictor of the minimal luminal diameter at follow-up and ultimately the net gain, which was 0.4 mm less after balloon angioplasty than after stent implantation.2,3 The loss index was 6 percentage points lower in the balloon-angioplasty group than in the stenting group (29 percent vs. 35 percent), also suggesting that the lesions treated with balloon angioplasty were underdilated.4

Allan G. Adelman, M.D.
Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada

4 References

1. 1

   Versaci F, Gaspardone A, Tomai F, et al. A comparison of coronary-artery stenting with angioplasty for isolated stenosis of the proximal left anterior descending coronary artery. N Engl J Med 1997;336:817-822
   Full Text | Web of Science | Medline

2. 2

   Beatt KJ, Serruys PW, Luijten HE, et al. Restenosis after coronary angioplasty: the paradox of increased lumen diameter and restenosis. J Am Coll Cardiol 1992;19:258-266
   CrossRef | Web of Science | Medline

3. 3

   Cohen EA, Lesperance J, Sykora K, Bourassa MG, Schwartz L. A distinction between process and outcome of lumen renarrowing after coronary angioplasty. J Am Coll Cardiol 1994;73:962-964
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4. 4

   Kuntz RE, Gibson CM, Nobuyoshi M, Baim DS. Generalized model of restenosis after conventional balloon angioplasty, stenting and directional atherectomy. J Am Coll Cardiol 1993;21:15-25
   CrossRef | Web of Science | Medline

Author/Editor Response

The authors reply:

To the Editor: Clinical evaluation of the patients was routinely carried out in the outpatient clinic by physicians not directly involved in the study. Furthermore, quantitative analysis of the vessels was performed by two observers who were not involved in the study and were blinded to its aims.

The size of the balloons and the inflation pressures used in our study were chosen to achieve a balloon:artery ratio close to 1:1, which is considered to be the ideal ratio for coronary angioplasty.1 The diameter of the balloon should be chosen carefully; undersizing (balloon:artery ratio, <0.9) can result in substantial residual stenosis, whereas oversizing (balloon:artery ratio, >1.2) increases the risk of dissection and acute complications.1 In our study, the balloon:artery ratio was 0.97, which is quite close to the ideal size (this ratio can be derived from the data in Table 1 and Table 3 of our article). Conversely, the use of Palmaz–Schatz stents requires a higher inflation pressure, and balloon oversizing is needed to achieve optimal expansion of the stent.1

Finally, we would like to emphasize that our prospective study shows a clear superiority of stenting over balloon angioplasty in terms of both the event rate and the restenosis rate in a well-selected and homogeneous group of patients (i.e., those with an isolated proximal stenosis of the left anterior descending coronary artery). In contrast, the two largest randomized, multicenter studies comparing stenting with coronary angioplasty 2,3 enrolled patients who were heterogeneous with regard to both the location of coronary stenoses and the number of diseased vessels, resulting in confounding of the findings. Indeed, in one of the studies,2 the actuarial rate of late event-free survival did not differ statistically between patients treated with angioplasty and those treated with stenting, although the latter group had a larger luminal diameter at follow-up. In the other study,3 patients who underwent stent implantation had a better actuarial rate of late event-free survival than those treated with angioplasty, although the luminal diameter at follow-up did not differ statistically between the two groups. Furthermore, a recent retrospective analysis of the results of the Stent Restenosis Study 4 showed that stenting does not have any clinical advantage over angioplasty in vessels other than the left anterior coronary artery.

Francesco Versaci, M.D.
Achille Gaspardone, M.D.
Pier A. Gioffrè, M.D.
Università di Roma Tor Vergata, 00149 Rome, Italy

4 References

1. 1

   Safian R, Freed M. Coronary intervention: preparation, equipmentand technique. In: Freed M, Grines C, Safian R, eds. Manual of interventional cardiology. Birmingham, Mich.: Physicians' Press, 1996:1-61.
   

2. 2

   Fischman DL, Leon MB, Baim DS, et al. A randomized comparison of coronary-stent placement and balloon angioplasty in the treatment of coronary artery disease. N Engl J Med 1994;331:496-501
   Full Text | Web of Science | Medline

3. 3

   Serruys PW, de Jaegere P, Kiemeneij F, et al. A comparison of balloon-expandable-stent implantation with balloon angioplasty in patients with coronary artery disease. N Engl J Med 1994;331:489-495
   Full Text | Web of Science | Medline

4. 4

   Heuser RR, Wong SC, Chuang YC, et al. The LAD subgroup in the Stent Restenosis Study (STRESS): the most pronounced antirestenosis effect of stenting. Eur Heart J 1995;16:Abstr Suppl:291-291 abstract.
   Web of Science | Medline

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