Abstract
Transcatheter management of valvular and structural heart disease is the most growing aspect of interventional cardiology. While the early experience was limited to patients who were not candidate for surgery, the continuous improvement in the efficacy and safety expanded its use to different degree depending on the procedure and the disease involved. The cost of these procedures is a major concern for health care in developed world. Cost-effectiveness of these transcatheter structural procedures varies depending on the procedure itself, the burden of the underlying disease, the feasibility and cost of both the Transcatheter and surgical procedures. In this review, we turn now to a specific discussion of the medical economics of percutaneous valvular and structural interventions.
1
Introduction
Structural heart disease is the field of interventional cardiology that may well witness the greatest growth in the next 10 years . The field of structural interventional cardiology was first developed with transcatheter valvuloplasty of the mitral valve followed by the introduction of closure devices of atrial septal defects (ASD) and patent foramen ovale (PFO). Importantly, the recent introduction of transcatheter aortic valve replacement (TAVR) and the development of new transcatheter techniques to manage mitral regurgitation promise an expected growth of 30% in the volume of structural procedure over the next decade . This estimated growth is based on the expected increase in incidence of aortic and mitral valve disease in the future due to aging of the population in addition to greater penetration of these methods to reach broader populations. Analysis based on three large population-based epidemiological studies showed that the prevalence of aortic and mitral valve disease in the population was estimated to be 2.5% but ranged from less than 1% for those under 54 years old to 4% to 8% by age 65 to 74 and 12% to 14% over age 75 .
The approval of the Edwards Sapien valve (Edwards Lifesciences, Irvine, CA) in 2007 and the CoreValve (Medtronic, Minneapolis, MN) shortly thereafter in Europe led to the performance of more than 60,000 TAVR procedures outside of the United States (US) in 2011 . In the United States, the Edwards Sapien valve was approved in 2011 and the CoreValve was approved in 2014. It is expected that TAVR volume will grow from 2000 per year in 2012 to 25,000 per year after 2015, especially after TAVR was shown to be a viable option in not only inoperable patients but also in operable but high risk patients . Similarly, many advances in the transcatheter management of mitral regurgitation are evolving . Currently the MitraClip is the only transcatheter-approved therapy for mitral regurgitation in the US, but there are many other devices available around the world.
All these advances in the transcatheter management of previously surgically managed conditions led to a different degree of change in practice around the world. Most of these transcatheter procedures are effective and are associated with comparable outcomes to surgery while being less invasive. However, they are associated in many cases with higher costs. In light of this, we turn now to a specific discussion of the medical economics of percutaneous valvular and structural interventions.
1.1
Cost effectiveness analysis and decision making
The primary goal of cost-effectiveness analysis is to evaluate different health care intervention options in common terms so that policy and other decision makers can be informed of the most efficient method of producing extra health benefits from among the alternative ways that health care dollars can be distributed. The metric used to assess incremental cost effectiveness is the incremental cost-effectiveness ratio (ICER). An ICER is defined as the ratio of incremental costs to incremental health benefits of treatment 1 compared to treatment 2, or ICER = (C1 − C2)/(HB1 − HB2); where C1 and C2 are cost for treatment 1 and 2, respectively and HB is the health benefit of treatment 1 and 2, respectively .
The ICER defines the cost that should be assumed for gaining one unit of output. In other words, if one of the alternatives is the usual practice, then it will tell us how much it will cost to gain a unit of outcome when moving from the usual practice to a new alternative. The health benefit may be measured in any sensible unit, such number of myocardial infarctions averted, but most studies use the conventional option of measuring clinical benefits as either the number of added life-years (LYs) or quality adjusted life years (QALYs) . Both of these approaches require estimation of life expectancy with and without the intervention being considered.
When assessing whether a treatment is cost effective, a requirement for threshold can arise when policy makers seek a benchmark to compare different treatments and judge different studies. In general, wealthier countries may be willing to pay more (i.e. accept higher threshold) for a given treatment than poorer countries . In the United States, a cost-effectiveness ratio < $50,000 per LY or QALY is frequently regarded as economically attractive, in part because it approximates the cost of providing chronic hemodialysis to patients with renal failure, at a cost that meets willingness-to-pay through Medicare . Conversely, an ICER of > $100,000 per added LY or QALY is frequently regarded as economically unattractive. The range between these two benchmarks is the gray zone in which there is no consensus on whether a treatment is economically acceptable . However, assigning the same ICER threshold for different treatment in wide range of diseases and different burden of this disease may not be reasonable. Some countries may assign a general threshold for most cases, but allow for a higher threshold for treatment that relieves considerable burden of illness, i.e. “the rule of rescue”. For example in Netherland, the average acceptable ICER is around €20,000, but an ICER of €80,000 per QALY will be acceptable for illnesses associated with a considerable disease burden . Similarly in Great Britain the limit of acceptable ICER varies between £20,000 and £30,000 depending on the burden of the disease .
2
Transcatheter versus surgical closure of secundum ASD in adults
Transcatheter ASD closure was shown to be a feasible option for the management of secundum ASD in adults . Outcome analysis of a cohort of 718 ASD closures performed between 1988 and 2005 that included 383 surgical ASD closures and 335 transcatheter ASD closures showed no difference in mortality at 5 years between the two strategies (5.3% transcather vs. 6.3% surgical; P = 1.00), but transcatheter intervention was associated with a higher re-intervention rate at 5 years (7.9% vs. 0.3%, p = 0.0038) .
Following ASD closure, there was no difference in new-onset CHF (5.0% vs. 3.0%, p = 0.30) or stroke/TIA (1.6% vs. 1.8%, p0.99) between patients undergoing surgical versus transcatheter ASD closure. Furthermore, there was a higher outpatient physician visits per patient (7.5 vs. 6.4, p 0.001) and critical care days per patient (0.24 vs. 0.14, p = 0.001) in the surgical cohort. There was no difference in the emergency department visits between the 2 groups (0.92 vs. 0.98, p = 0.61) .
Cost effectiveness on this cohort showed that the 5-year cost of surgical closure was $15,304 versus $11,060 for the transcatheter alternative. At 5 years, transcatheter closure was marginally more effective than surgery (4.683 ± 0.379 LY versus 4.618 ± 0.638 LY) . So it seems that whenever feasible, transcatheter ASD closure may offer a very promising cost effective alternative surgical closure.
2
Transcatheter versus surgical closure of secundum ASD in adults
Transcatheter ASD closure was shown to be a feasible option for the management of secundum ASD in adults . Outcome analysis of a cohort of 718 ASD closures performed between 1988 and 2005 that included 383 surgical ASD closures and 335 transcatheter ASD closures showed no difference in mortality at 5 years between the two strategies (5.3% transcather vs. 6.3% surgical; P = 1.00), but transcatheter intervention was associated with a higher re-intervention rate at 5 years (7.9% vs. 0.3%, p = 0.0038) .
Following ASD closure, there was no difference in new-onset CHF (5.0% vs. 3.0%, p = 0.30) or stroke/TIA (1.6% vs. 1.8%, p0.99) between patients undergoing surgical versus transcatheter ASD closure. Furthermore, there was a higher outpatient physician visits per patient (7.5 vs. 6.4, p 0.001) and critical care days per patient (0.24 vs. 0.14, p = 0.001) in the surgical cohort. There was no difference in the emergency department visits between the 2 groups (0.92 vs. 0.98, p = 0.61) .
Cost effectiveness on this cohort showed that the 5-year cost of surgical closure was $15,304 versus $11,060 for the transcatheter alternative. At 5 years, transcatheter closure was marginally more effective than surgery (4.683 ± 0.379 LY versus 4.618 ± 0.638 LY) . So it seems that whenever feasible, transcatheter ASD closure may offer a very promising cost effective alternative surgical closure.
3
Medical economics of transcatheter aortic valve replacement (TAVR)
It is estimated that 3.4% of the population older than 75 years has severe aortic stenosis with 350,000 patients in the US alone . Forty percent of these patients do not get surgical intervention secondary to being considered either inoperable or at very high surgical risk. TAVR was developed as an alternative for surgical valve replacement. TAVR treats aortic stenosis by displacing and functionally replacing the native valve with a bioprosthetic valve delivered on a catheter (Edward Sapien) or trileaflet porcine pericardial valve on a self-expanding nitinol frame (CoreValve) through the femoral artery (transfemoral approach, TF-TAVR) or the left ventricular apex (transapical placement, TA-TAVR). It is estimated that there are approximately 102,558 TAVR candidates in North America and 189,836 TAVR candidates in Europe .
3.1
Cost effectiveness of transcatheter aortic valve replacement vs. medical therapy in inoperable patients
Symptomatic severe aortic stenosis in the absence of definitive treatment leads to progressive symptoms, functional decline, and death . In patients who are considered not candidates for surgical aortic valve replacement (SAVR), medical therapy was not effective in slowing the expected outcomes. The introduction of TAVR offered an alternative for this patients’ population.
The evidence supporting the use of TAVR in patients with severe aortic stenosis who are not surgical candidates comes from Cohort B of the placement of aortic transcatheter valves (PARTNER) trial that randomized 358 patients with aortic stenosis who were not considered to be suitable surgical candidates to either medical management (inclusive of balloon valvuloplasty) or TAVR. The trial found an impressive absolute 20% reduction in 1-year mortality for TAVR compared with standard therapy in this population (30.7% TAVR vs. 50.7% standard therapy; HR = 0.55; 95% CI; [0.40–0.74]; P < 0.001). However, TAVR was associated with a higher incidence of major strokes (5.0% vs. 1.1%, P = 0.06) and major vascular complications (16.2% vs. 1.1%, P < 0.001) .
An economic evaluation of the PARTNER B cohort showed that TAVR was associated with a mean cost of $42,806 for the initial procedure and $78,542 for the hospitalization. Follow-up costs through 12 months were lower with TAVR compared to standard therapy ($29,289 vs. $53,621; P < 0.001). The cumulative 1-year costs remained higher with TAVR ($106,076 vs. $53,621; P < 0.001). TAVR would increase discounted life expectancy by 1.6 years (1.3 quality-adjusted life-years) at an incremental cost of $79,837. TAVR use was associated with ICER of $50,200 per LY gained and $61,889 per QALY gained . Fig. 1 summarizes the cost assessment of medical management vs. TAVR in PARTNER trial Cohort B.
