Three international guidelines recommend SET as a first line treatment for patients with IC (2-4), supported by cost-effectiveness analyses (13, 16-20). Unfortunately, the availability of SET programs in Europe is low (10, 22). Some consider the substantial investments to obtain nationwide implementation of SET programs as a problem (13). Our findings implicate that the initial investments to increase SET availability in other countries may be beneficial when guidelines and therefore the SCM are followed. Despite that the Dutch have a well-organised community based SET network should not be an excuse for other European countries but a motivation to implement such a network. Furthermore SCM implementation effects and thus cost-savings may even be larger since most foreign health care systems have low penetration of (community-based) SET programs and thus a potential lower threshold for invasive vascular interventions. Moreover the calculated savings of a SCM approach in this study are in euros, while a reduction of morbidity and mortality ratios might account as well.
Makris et al. claimed a 100% SET availability in the Netherlands in 2012 (10). The present study demonstrated that a mere 14% of the IC patients were actually referred to SET in 2009. The discrepancy between a relatively low percentage of SET referrals and high availability of SET programs might be explained by the combination of conflicting reimbursement issues, increased patients' and physicians' enthusiasm for interventional procedures (16), and a lack of appreciation of SET (9). The latter might be caused by ambiguities in contemporary guidelines, which may be responsible for a too liberal use of invasive procedures in patients with IC due to aortoiliac lesions as stated in the TASC (4). In contrast the NICE guideline suggest to initiate this type of lesion with SET (3). Several large trials show inconclusive results concerning treatment of aortoiliac lesions (23-26). In the present study, 28% of the patients received a primary revascularization, of which 51% concerned aortoiliac lesions. More than half (58%) of the included patients were even assumed to have received a walking advice. The present study therefore clearly demonstrates that the TASC II / NICE guidelines (restricting
interventions to patients not responding to SET) are largely neglected in Dutch practices. A nationwide implementation of a SCM might tackle these issues, whereas expected cost-savings as presented in this study may facilitate current conflicting issues in reimbursement.
Moreover , a SCM may have substantial influence on IC patients' individual treatment strategy. It is known that patients suffering from IC, regardless of the severity of the walking restriction, have a range of other limitations (27). Initiating treatment with SET may provide awareness of important functional restrictions in daily life other than caused by IC (e.g. COPD, congestive heart failure, osteoarthritis, spinal stenosis, equilibrium disorders). So following a SCM, may prevent potentially futile vascular interventions in multimorbid patients who are limited by more than just IC. Furthermore, once (successful) invasive treatment has been performed, recurrent ipsilateral or newly developed contralateral obstructions are likely again treated by invasive means too, contributing to a high re-interventions ratio (35%) in the INT group. Surprisingly, this was also found by others (16) and is in line with reported patency rates of endovascular revascularizations (28, 29). Additionally, initiating a SET first policy might not meet the contemporary articulate and demanding patient, focused on a quick fix of the problem. Our findings suggest that a SCM, with a three-month trial period preceding invasive treatment, in which patients not responding to SET are eligible for invasive treatment might decrease the number of interventions.
Our study has limitations inherent to its retrospective character. Some might argue that selection bias may have influenced the results, since patients with more severe IC complaints or with a specific atherosclerotic lesion may preferentially have been treated by invasive means. However, all included patients had IC classified as Fontaine II and according to contemporary guidelines should have received SET as a primary treatment (2-4). In addition, we applied a correcting factor, in our (best-case scenario) calculations referral rate was set at an 80% ratio (instead of the guidelines' 100%), permitting the remaining 20% to be treated based on personal preference of the patient or of the vascular surgeon.
Furthermore our study showed differences in patient characteristics between groups (age, gender and CHF). Unfortunately we were not able to adjust our analyses for these covariates due to privacy limitations of the insurance company database. Our findings reveal that young males were treated more frequently with revascularization compared to older patients or females. This phenomenon might reflect assumptions and indirect evidence suggesting that invasive treatment should be preferred in a working age population as recovery is deemed faster. The same might be the case in the assumption that since endovascular treatment for aortoiliac lesions is more durable compared to femoropopliteal lesions, this warrants an intervention in aortoiliac lesions (28). However, as far as we know, no evidence substantiates such an invasive first line treatment for certain IC subgroups.
A formal cost-effectiveness study could not be performed since the insurance company's database lacks data on treatment effect or outcome. Furthermore, costs
related to an intervention of the ipsi- or contralateral leg could not be identified which may have biased total costs of the INT group. However, this limitation is relative as walking exercise pertains to both legs.
Reimbursement issues in the Dutch health care system remain an issue. Optimization of a SCM depends on political decision-making and awareness of health care insurers concerning the functional and financial advantages of SET. The impact of a SCM implementation on the Dutch as well as European society should be subject to future research.