SAVAL trial finds no gains with custom drug-eluting stents in PAD below the knee

Hans van Overhagen (image credit: CIRSE)

Day one of the Cardiovascular and Interventional Radiological Society of Europe (CIRSE) 2022 annual meeting (10–14 September, Barcelona, Spain) put a strong focus on peripheral arterial disease (PAD).  At a FIRST@CIRSE session, Hans van Overhagen (Haga Teaching Hospital, Den Haag, The Netherlands), as European principal investigator, presented the primary results of the SAVAL trial.

Comparing the Saval drug-eluting stent (DES) below-the-knee (BTK) vascular stent system (Boston Scientific) and percutaneous transluminal angioplasty (PTA) in the infrapopliteal lesions of chronic limb-threatening ischaemia (CLTI) patients, the trial failed to meet its primary effectiveness and safety endpoints.

The primary objectives of the SAVAL study were to evaluate one-year primary vessel patency and safety following use of the Saval DES, which is designed specifically for BTK interventions, Van Overhagen asserted. The stent is made of nitinol and polymer-coated, with paclitaxel.

The presenter then explained that the SAVAL trial is a prospective, multicentre, randomised superiority trial of patients with symptomatic infrapopliteal artery lesions and Rutherford category 4–5 CLTI. The patients were assigned 2:1 to treatment with Saval DES or PTA.

The primary safety endpoint (non-inferiority) is 12-month major adverse event (MAE)-free rate, defined as a composite of above-ankle amputation of the index limb, major reintervention and 30-day mortality, the presenter elaborated.

Providing further details of the study, Van Overhagen stated that a total of 201 patients were enrolled and randomly assigned to treatment (n=130 DES, n=71 PTA) at 39 study centres in Belgium, France, The Netherlands, the USA, and Japan.

In terms of primary results, Van Overhagen reported a high technical success rate of 100% in the DES group and 98.7% in the PTA group.

However, “the primary effectiveness endpoint of superior 12-month primary patency was not met,” the presenter relayed—the figure was 68% in the DES group and 76% in the PTA group. “The primary safety endpoint of non-inferior 12-month MAE-free rate was [also] not met,” Van Overhagen supplemented, citing the results of 91.6% and 95.3% respectively for the DES and PTA groups, while freedom from all-cause mortality was 92.2% versus 89.9%.

Van Overhagen shared the rationale behind conducting the study: CLTI is a condition with “few effective endovascular options for infrapopliteal artery revascularisation” and DESs have yielded positive results in previous studies. This reflects what Van Overhagen highlighted in an earlier presentation he gave on DESs—both an endovascular approach and revascularisation are key to optimal treatment of CLTI.

In view of the primary results, Van Overhagen told delegates that “patient follow-up will continue through three years in-office with vital status assessment through five years, as specified in the study protocol […] We believe that given the impact of CLTI on limb and life, continued innovation to provide minimally invasive treatments is needed”.

In another PAD day session, Van Overhagen presented on the devices currently available and evidence to support the use of DESs specifically.

Van Overhagen began his first presentation of the day by underlining that the “cornerstone” of CLTI is revascularisation—”we try to get unobstructed blood flow all the way into the foot and avoid amputation”. The presenter went on to acknowledge that “we all know that endovascular treatment is less invasive. This is why, where possible, we use an endovascular approach”.

The presenter then proceeded to explain the origin of drug-eluting balloons (DEB) and DES: “[they] have been introduced in order to try to reduce restenosis […] we try to diminish the amount of intimal hyperplasia”. The Dutch PADI trial, for which Van Overhagen was principal investigator, compared PTA with bare metal stents (BMS) to DES and, at two-year follow-up, there were almost twice as many major amputations in the former group, a trend which was also observed at five years.

“Our initial conclusions were that DES BTK in CLTI achieved improved patency, a trend towards fewer major amputations [and indicated] a need for dedicated self-expandable and longer stents,” Van Overhagen reported. Further analysis out to ten years has also shown DES BTK to be safe and cost-effective, the presenter concluded.