Comparison of the Resource Utilization Between Simultaneous Strategy and Staged Strategy to Treat Two-Vessel Coronary Artery Disease by Percutaneous Coronary Intervention

Abstract: Objectives. The purpose of this study was to compare medical resource use, such as total device cost, total contrast volume, and total fluoroscopy time between the staged and simultaneous strategies for treating two-vessel disease (2VD) by percutaneous coronary intervention (PCI). Background. 2VD can be treated by the staged strategy or the simultaneous strategy. Compared to the staged strategy, the simultaneous strategy may reduce medical resource use. Methods. We identified a staged group (138 patients) and simultaneous group (62 patients) from our PCI database between January 1, 2008 and December 31, 2010. Total PCI device cost, total contrast volume, and total fluoroscopy time were compared between the two groups. Results. Total costs for the staged group and the simultaneous group given in United States dollars were $21,289 ± 5633 and $16,571 ± 5530, respectively (P<.0001). Total contrast volumes for the staged group and the simultaneous group were 299 ± 79 mL and 194 ± 62 mL, respectively (P<.0001). Total fluoroscopy times for the staged group and the simultaneous group were 60 ± 27 minutes and 40 ± 15 minutes, respectively (P<.0001). In multivariate analysis, the simultaneous strategy was significantly associated with low cost, small contrast volume, and short fluoroscopy time even after controlling for age, sex, acute coronary syndrome, and lesion complexity. Conclusions. Compared to the staged strategy to treat 2VD by PCI, the simultaneous strategy reduced medical resource use, i.e., total device cost, total contrast volume, and total fluoroscopy time.

J INVASIVE CARDIOL 2011;23(11):454-459

Key words: fluoroscopy, contrast volume, cost-effectiveness, multivessel disease

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Advances in devices and techniques have increased the use of percutaneous coronary intervention (PCI) to treat coronary artery disease, and have changed the indications for PCI.^1,2 Although two-vessel coronary artery disease (2VD) including the proximal left anterior descending artery (LAD) is still a good indication for coronary artery bypass graft surgery, PCI for 2VD is a class I or class IIa indication in the current guidelines.³ Therefore, PCI for 2VD is not unusual in routine clinical practice.⁴ When performing PCI for 2VD, there are two different strategies: the staged strategy and the simultaneous strategy. With the staged strategy, PCI for 2VD is performed in two separate sessions. With the simultaneous strategy, PCI for 2VD is performed in a single session. The staged strategy has been performed in specific situations, such as ST-elevation myocardial infarction (STEMI),^5,6 because the simultaneous strategy has a potential risk of severe adverse events (for example, simultaneous acute stent thrombosis or simultaneous acute vessel closure). However, the development of new stents and the use of dual-antiplatelet therapy has reduced the risk of acute stent thrombosis and vessel closure.⁷ Although recent analysis did not support the simultaneous strategy in STEMI and multivessel disease,^8,9 some studies suggested the efficacy and safety of the simultaneous strategy even in an emergent setting.^10,11

Although PCI is a less invasive therapy for coronary artery disease, PCI is a costly therapy.¹² In addition, it is very likely that PCI for multivessel coronary artery disease would cost more than PCI for single-vessel disease.¹³ Therefore, it is important to reduce medical resource use when PCI is performed to treat 2VD. The simultaneous strategy may reduce total medical resource use, such as device cost, because guidewires or balloons may be reused after treating the first lesion. The purpose of this study was to compare the medical resource use, such as total device cost, total contrast volume, and total fluoroscopy time between the staged strategy and the simultaneous strategy for the treatment of 2VD by PCI.

Methods

Patients and lesions. We identified the staged group and the simultaneous group from our PCI database between January 1, 2008 and December 31, 2010. The inclusion criteria were: 1) patients who had PCI for 2VD in two sessions; 2) patients who had PCI for 2VD in one session; and 3) 2VD was either the combination of the LAD and right coronary artery (RCA), the combination of the LAD and left circumflex artery (LCX), or the combination of the RCA and LCX. Patients with lesions in large branches of the main coronary vessels were also included. Patients were excluded if the interval between the 2 sessions was >30 days, or if PCI was used to treat a saphenous vein graft. The patients who had PCI for 2VD in two sessions were identified as the staged group; the patients who had PCI for 2VD in one session were identified as the simultaneous group. 

The complexity of each lesion was classified into simple or complex. Simple was defined as ACC/AHA type A or B1, and complex was defined as ACC/AHA type B2 or C.¹⁴ Therefore, the combinations of lesion complexity were either both simple (simple and simple), simple and complex, or both complex (complex and complex). Chronic total occlusion was defined as total occlusion ≥3 months. Other clinical criteria were defined as follows: Acute coronary syndrome was defined as STEMI, non-ST elevation myocardial infarction (NSTEMI), or unstable angina. Chronic renal failure was serum creatinine level >2.0 mg/dl. Contrast-induced nephropathy was defined as an elevation in serum creatinine ≥0.5 mg/dl or 25% using serum creatinine levels measured before and after PCI.¹⁵ This study was approved by the Institutional Review Board.

PCI procedures. PCI was performed using standard techniques. The choice of devices such as guidewires, balloons, and stents was left to the discretion of the operators. Intravascular ultrasound (IVUS) was routinely used for almost all lesions. In our medical center, the operators favored simultaneous PCI in the following situations: 1) cardiogenic shock associated with multivessel stenosis; 2) scarce access site due to peripheral artery disease or the presence of a shunt for hemodialysis; and 3) the presence of simple lesions in the target vessels. In contrast, staged PCI was favored in the following situations: 1) high-risk patients for contrast-induced nephropathy; and 2) complex lesions in the target vessels that required a larger volume of contrast media and/or longer fluoroscopy time. However, the final choice of staged or simultaneous PCI was left to the discretion of the operators. The method used to prepare each patient for contrast injection, such as sufficient hydration by normal saline, was also left to the discretion of the operators. 

Medical resources for PCI. We adopted total device cost, total contrast volume, and total fluoroscopy time as indices of medical resource use for PCI. We calculated total device cost, total contrast volume, and total fluoroscopy time for each patient. In the staged group, total device cost, total contrast volume, and total fluoroscopy time were the sum of those values in the first and second sessions. Total device cost was defined as the sum of all reimbursement prices, but did not include staff fees and catheter laboratory charges. The reimbursement price for each device is strictly set by the Ministry of Health, Labor, and Welfare in Japan.¹⁶

Statistical analysis. Data are presented as percentages for categorical variables and as mean ± standard deviation for continuous variables. The number of devices used, total device cost, total contrast volume, and total fluoroscopy time were compared between the staged and simultaneous groups. Categorical data were compared using the χ² test. Continuous data were compared using the Mann Whitney U test. Multivariate logistic regression analyses were performed to investigate whether the simultaneous strategy was associated with low cost, small contrast volume, or short fluoroscopy time after controlling for clinical and demographic factors. In this model, the lowest tertile of total device cost, total contrast volume, and total fluoroscopy time were defined as low cost, small contrast volume, and short fluoroscopy time, respectively. Cost, contrast volume, and fluoroscopy time were used as the dependent variables. Clinical and demographic factors, such as age, sex, acute coronary syndrome (versus non-acute coronary syndrome), and lesion complexity were entered as the independent variables. Odds ratios and 95% confidence intervals were calculated. The analyses were performed using SPSS 13.0/Windows (SPSS, Inc.) statistical software. A P-value <.05 was considered significant.

Results

Between January 1, 2008 and December 31, 2010, there were 1189 patients (1488 PCI) treated by PCI in our medical center. There were 62 patients who had simultaneous PCI for 2VD. There were 551 patients who had at least 2 PCI during this period. In 551 patients, there were 138 patients who had staged PCI for 2VD (the duration between the 2 sessions was <30 days). Therefore, a total of 200 patients were included in this analysis, of which 138 patients were in the staged group and 62 were in the simultaneous group.

Patients and lesion characteristics are shown in Table 1. The prevalence of acute coronary syndrome was similar between the two groups. Other clinical characteristics were different between the two groups. Although lesion complexity and the prevalence of chronic total occlusion were similar, the combination of lesion site was significantly different between the two groups. The combination of LAD and LCX in the simultaneous group was higher than in the staged group. The comparison of PCI devices is shown in Table 2. Whereas the number of stents and total stent length were similar between the two groups, the number of guiding catheters, guidewires, intravascular ultrasound (IVUS) catheters, and rotablation burrs in the simultaneous group was significantly less than in the staged group. The comparison of total device cost is shown in Figure 1. Total costs for the staged group and the simultaneous group were (US) $21,289 ± 5633 and $16,571 ± 5530, respectively (P<.0001). The total contrast volumes for the staged group and the simultaneous group were 299 ± 79 mL and 194 ± 62 mL, respectively (P<.0001). The total fluoroscopy times for the staged group and the simultaneous group were 60 ± 27 minutes and 40 ± 15 minutes, respectively (P<.0001). As higher use of IVUS and rotablator burrs might increase the difference in costs, we performed further analyses and compared the costs between the groups after excluding the costs of IVUS and rotablator burrs. The total costs without IVUS and rotablator burrs for the staged and simultaneous groups were $16,763 ± 4636 and $14,508 ± 5088, respectively (P=.001).

Multivariate logistic regression analyses for low cost, small contrast volume, and short fluoroscopy time are shown in Table 3. In multivariate analysis, the simultaneous strategy was significantly associated with low cost, small contrast volume, and short fluoroscopy time after controlling for age, sex, acute coronary syndrome, and lesion complexity.

We also compared in-hospital outcomes between the two groups (Table 4). There were 4 in-hospital deaths in the total population. These 4 patients were admitted due to ACS (2 had NSTEMI and 2 had STEMI). There were no deaths among the non-ACS patients. There was no stent thrombosis in either group. The delta creatinine between the two groups was not significantly different. Although the prevalence of in-hospital death and contrast-induced nephropathy was similar between the two groups, the duration of hospital stay was significantly shorter in the simultaneous group than in the staged group.

Discussion

We investigated whether the simultaneous strategy has any value in reducing medical resource use in 200 patients who had PCI for 2VD. Although the choice of the staged or simultaneous strategy was left to the discretion of the operators, lesion complexity, including chronic total occlusion and final stent length, was similar between the strategies. Our results showed that total device cost, contrast volume, and fluoroscopy time were significantly lower in the simultaneous group ($16,571 ± 5530, 194 ± 62 ml, and 40 ± 15 minutes, respectively) than in the staged group ($21,289 ± 5633, 299 ± 79 ml, and 60 ± 27 minutes, respectively). Multivariate analyses also showed that the simultaneous strategy was associated with low cost, small contrast volume, and short fluoroscopy time after controlling for confounding factors.

There are a few previous studies that compared the simultaneous and staged strategies. Nikolsky et al compared the outcomes of PCI for multivessel disease between the two strategies.¹⁷ Although their study period covered 1997 to 1998, both simultaneous PCI and staged PCI had a high primary success rate and low incidence of in-hospital complications. Recently, Politi et al reported the efficacy and safety of the simultaneous strategy for STEMI, in which 214 patients were randomly assigned to culprit lesion-only revascularization, staged revascularization, or simultaneous revascularization.¹⁰ However, there are no previous studies that compared medical resource use between the simultaneous and staged strategies to treat 2VD by PCI.    

Although staged PCI for multivessel disease is a well known strategy,^5,6 previous reports on the use of simultaneous PCI for 2VD are scarce. Simultaneous PCI for 2VD has been considered a risky strategy in the past, because acute vessel complications such as acute (or subacute) stent thrombosis and acute vessel closure in the two culprit lesions can be fatal. Although the rate of acute or subacute thrombosis was more than 10% in the early stent era,^18,19 the rate of acute or subacute thrombosis is only about 1% in the current stent era.⁷ There was no stent thrombosis in our study population. Another concern is the excessive use of contrast media during simultaneous PCI; however, the rate of contrast-induced nephropathy was similar between the groups. Therefore, simultaneous PCI for 2VD is not necessarily a risky strategy in the current stent era.

It is not difficult to explain the reduced costs with the simultaneous strategy. The simultaneous strategy should reduce the number of guiding catheters, guidewires, IVUS catheters, balloons, and rotablator burrs. The operators could use the same guidewires or balloons for both vessels in the simultaneous strategy; however, reuse is not allowed in the staged strategy. Therefore, reduced device cost is the main reason the simultaneous strategy was more cost-effective. There are several reasons the simultaneous strategy reduced the total contrast volume and fluoroscopy time. When treating the LAD and LCX, the simultaneous strategy might reduce the need to perform fluoroscopy in different planes. Furthermore, the use of the simultaneous strategy itself might add pressure on the operators to reduce total contrast volume and fluoroscopy time.

Study limitations. This study was a single-center, retrospective study. Although lesion complexity and final stent length were similar between the two groups, there is a risk of patient selection bias. Second, the total device cost was calculated by the reimbursement price set by the Ministry of Health, Labor, and Welfare in Japan, which may not apply to other health care systems. Third, our retrospective analysis could not analyze the appropriateness criteria for each PCI procedure;²⁰ however, the operators and attending physicians discussed the indications for each PCI procedure. Fourth, as serum creatinine levels were not measured prospectively, we could not set clear criteria for the timing of serum creatinine measurements after PCI. Therefore, the incidence of contrast-induced nephropathy might have been underestimated. Fifth, the LAD and LCX combination was performed more commonly in the simultaneous group, biasing that group toward lower costs and exaggerating the difference in resource use between the groups. Sixth, our cost analysis did not include physician fees, staff salaries, hospital stay fees, or catheter laboratory fees, because these costs are not the same in the Japanese system compared with Western countries. This might have led to underestimation of the difference in costs between the two strategies. Seventh, patients in whom simultaneous PCI was planned but the second vessel was aborted due to difficulties during the first procedure were not included in the simultaneous group. Finally, our study population included ACS patients. The ACC/AHA guidelines for STEMI do not recommend PCI for non-culprit lesions in patients with STEMI, although the level of evidence is C.²¹

Conclusions

Compared to the staged strategy to treat 2VD by PCI, the simultaneous strategy reduced medical resource use, such as total device cost, total contrast volume, and total fluoroscopy time. Although our study population was not powered to detect differences in adverse outcomes, the rate of adverse outcomes between the two strategies was similar. The results of our retrospective study support the need to prospectively evaluate the impact of the simultaneous strategy on medical resource use in the future.

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From the Division of Cardiovascular Medicine, Department of Integrated Medicine I, Jichi Medical University Saitama Medical Center, Saitama, Japan.
Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. The authors report no conflicts of interest regarding the content herein.
Manuscript submitted June 27, 2011, provisional acceptance given July 15, 2011, final version accepted August 15, 2011.
Address for correspondence: Kenichi Sakakura, MD, Division of Cardiovascular Medicine, Department of Integrated Medicine I, Jichi Medical University Saitama Medical Center, Amanuma 1-847,Omiya, Saitama, 330-8503 Japan. Email: ZXH03005@nifty.ne.jp