2.1. Percutaneous Transluminal Angioplasty and Primary Stenting
The literature has documented two types of endovascular revascularization (ER) methods: percutaneous transluminal angioplasty (PTA) and primary stenting (PMAS) [
55]. However, there is a scarcity of prospective studies directly comparing the efficacy of PTA alone versus primary stenting. It is worth noting that mesenteric stenoses are commonly found at the ostium, making them susceptible to recoil following PTA [
56,
57,
58].
Research focused on revascularization of ostial renal artery stenosis has indicated that elastic recoil tends to transpire more frequently in cases of ostial stenoses, which can lead to the recurrence of stenosis if recoil is not prevented through stenting [
59,
60].
Based on case series and expert observations, it has been suggested that the majority of mesenteric artery stenoses occur at the origin of the vessel, with these stenoses often exhibiting substantial calcification [
57,
58].
The available evidence comparing both strategies is lacking for unequivocal data. A systematic review encompassing 328 patients and comparing mesenteric artery PMAS and PTA demonstrated a significantly higher technical success rate for PMAS (95% vs. 83%), with comparable symptom relief (91% vs. 89%) but a higher restenosis rate (35% vs. 21%) [
61]. In a more recent retrospective cohort study, a lower reintervention rate was reported for PTA in comparison to PMAS, although the observed difference did not achieve statistical significance. Initially, PTA appeared to yield better short-term outcomes; however, when analyzed over the duration of follow-up, no discernible difference was observed [
62].
Conversely, a retrospective study conducted by TURBA et al. [
63] explored the patency outcomes of different treatment approaches for SMA stenosis and demonstrated that PTA alone exhibited superior efficacy compared to PMAS or PTA followed by stenting (P < 0.031). Notably, the patency rates of the SMA following PTA alone were significantly better than when all stents were combined (P < 0.014). Regarding the outcomes associated with PTA versus stent placement (either primary or after PTA), no statistically significant difference was observed (P < 0.765) in the CA and IMA [
63].
Despite the limited quality of available evidence, the consensus among experts is strongly in favor of PMAS over PTA alone for the treatment of atherosclerotic mesenteric artery stenosis. This preference stems from the recognition that achieving technical success and ensuring adequate revascularization are considered primary objectives in these cases [
55]. This viewpoint is further supported by the 2017 Guidelines from the European Society for Vascular Surgery, by the American College of Radiology and more recently Guidelines from the Society for Vascular Surgery, which recommend primary mesenteric stenting as the indicated approach [
5,
64,
65].
The reported technical success rates for endovascular stent placement in these cases range from 85% to 100%. In contrast, the success rates for mesenteric arterial occlusions and lesions treated solely with PTA are comparatively lower, range 65% to 85% [
56].
All the characteristics listed in the previous studies are summarized in
Table 1.
2.2. Open Revascularization vs Endovascular Revascularization
In 1958, RS Shaw from the Massachusetts General Hospital reported the first successful open revascularization (OR) for CMI through the performance of superior mesenteric artery SMA endarterectomy. Subsequently, open surgical repair became the established standard treatment for CMI. This approach encompasses various techniques such as direct reimplantation on the aorta, antegrade or retrograde bypass grafting, and transaortic endarterectomy [
43].
The selection of the specific type of open reconstruction (e.g., antegrade or retrograde, single- or multiple-vessel, aortic- or iliac-based) is based on the patient’s clinical risk assessment and anatomical considerations [
66].
Despite the widespread adoption of the endovascular approach, the available data supporting its use have limitations in terms of evidence-based standards. Moreover, it remains unclear whether the early benefits of the endovascular approach outweigh the reduced long-term patency rates associated with it. The absence of randomized controlled trials (RCTs) directly comparing OR and endovascular revascularization (ER) further contributes to this knowledge gap.
The most comprehensive and rigorous study examining the perioperative and long-term outcomes of patients with CMI treated with either open or endovascular approaches is the systematic review and meta-analysis conducted by Alahdab et al. [
67] This study encompassed a total of 100 observational studies, including 22 comparative and 78 noncomparative studies, which collectively involved nearly 19,000 patients. The findings of the review indicate that the perioperative complication rate was higher in the open revascularization group, with a relative risk (RR) of 2.19 (95% confidence interval [CI], 1.84-2.60). However, there was no significant difference observed in the 30-day mortality rate between the open and endovascular groups (5.5% vs. 1.4%; RR, 1.57; 95% CI, 0.84-2.93). Regarding long-term outcomes, open revascularization was associated with a lower risk of recurrence at the 3-year mark, with an RR of 0.47 (95% CI, 0.34-0.66). However, there was no significant difference in the 3-year survival rate between the open and endovascular groups (RR, 0.96; 95% CI, 0.86-1.07).
In the meta-analysis conducted by Cai et al. [
68], involving 8 studies and 569 patients, no significant disparities were identified in perioperative mortality or survival rates between the open and endovascular groups. However, the endovascular group demonstrated a lower incidence of perioperative complications, albeit with a higher rate of recurrence. Conversely, Gupta et al. [
69] reported in their comprehensive analysis of 1939 patients that open repair exhibited a higher rate of perioperative complications. Remarkably, despite similar perioperative mortality and survival rates, the open repair group displayed superior 5-year primary patency (odds ratio [OR], 3.8; 95% CI, 2.4-5.8; P < .001) and 5-year freedom from recurrent symptoms (OR, 4.4; 95% CI, 2.8-7.0; P < .001) compared to the endovascular group. Turning to the meta-analysis conducted by Pecoraro et al. [
70], incorporating 43 studies and 1795 patients, the endovascular group exhibited lower rates of perioperative morbidity and mortality. Nevertheless, this group presented lower patency rates without a discernible difference in survival when compared to the open repair group. Meanwhile, Saedon et al. [
71], who analyzed 12 studies encompassing 7365 patients, reported no significant distinctions in perioperative morbidity, perioperative mortality, or survival between the open and endovascular groups. However, they observed a notable increase in patency (odds ratio [OR], 3.57; 95% CI, 1.83-6.97; P = 0.0002) within the open repair group. According to Van Petersen et al. [
72], ER offers the advantage of lower short-term morbidity but entails decreased long-term primary patency compared to OR. Both ER and OR exhibited similar rates of secondary patency, albeit with a higher reintervention rate after ER. In a more recent study by Menges et al. [
73], encompassing a single series of 63 patients, no significant differences were observed in terms of reintervention rate (82% after OR and 73% after ER, p = 0.14), 30-day mortality (0.0% after ER and 4.5% after OR, p = 0.069), 30-day morbidity (ER 9.8% vs. OR 31.8%, p = 0.030), or overall survival (OR 85% vs. ER 86%; p = 0.35) during a mean follow-up of 26 months. However, a substantially longer length of stay was noted after OR compared to ER (14 vs. 4 days; p <0.001).
The findings from meta-analyses and single series are in line with statewide and national observations regarding revascularization for CMI. Indes et al. [
74] studied patient outcomes for CMI revascularization in New York from 2000 to 2006. They found that ER became more popular, increasing from 28% to 75%. A lower perioperative mortality (11.0% vs. 20.4%), fewer mesenteric complications (6.9% vs. 17.1%), and reduced organ system complications (e.g., heart, lungs, infections) were reported in the ER group. Wolk et al. [
75] observed a rise in ER percentage from 0% in 2008 to 82% in 2017. In-hospital mortality was 2.8% (n = 1), and no significant mortality differences were found between treatment groups (OR 6.7%, n = 1 vs. ER 0%, n = 0; P = 0.42). However, major complications were more frequent after OR than ER (7% vs. 3%, P < 0.02). ER led to shorter hospital stays (11 ± 10 days vs. 21 ± 11 days; P < 0.01). No significant differences were seen in one-year primary patency (OR 91.6% vs. ER 96.8%; not significant [n.s.]), three-year primary patency (OR 91.6% vs. ER 80.6%; n.s.), and three-year symptom-free survival (OR 62.5% vs. ER 69.4%; n.s.). The authors concluded that while ER had comparable perioperative outcomes, it had a higher technical failure rate. Conversely, OR had excellent early and late technical success.
Based on meta-analyses, case series, and nationwide experience, evidence supports using endovascular-first in CMI patients. The approach is linked to fewer complications, shorter hospital stays, and lower costs. However, endovascular approach has higher rates of recurrent symptoms and reinterventions. Yet, long-term survival rates are comparable to open surgery, with a slight trend towards higher perioperative mortality in open surgery. Endovascular failures and recurrent symptoms don’t significantly increase the risk of death. Choosing endovascular-first allows open revascularization if needed.
Table 2 provides a summary of all the traits described in the studies listed above.
Reputable organizations like the Society of Vascular Surgeon [
5], European Society of Vascular Surgery [
64], American College of Radiology[
65], and Society of Interventional Radiologists recommend endovascular-first [
56].
2.3. Endovascular Revascularization: Balloon-Expandable Covered Stent vs Balloon-Expandable Bare Metal Stent
Revascularization of the SMA is considered the primary objective, while the CA and IMA are considered secondary targets if SMA revascularization is not feasible or if the clinical outcome is unsatisfactory [
5]. Over the past 15 years, endovascular intervention has surpassed open procedures as the most used treatment approach for CMI [
62].
Currently, there is no consensus regarding the optimal choice between balloon-expandable covered stents (CS) or balloon-expandable bare metal stents (BMS) for the treatment of CMI. However, emerging evidence suggests that CS may offer increased patency rates in CMI treatment [
76].
The CS forms a mechanical barrier, excluding the plaque and endothelium, thereby limiting intimal hyperplasia by preventing migration of macrophages into the endothelium. If allowed to migrate into the endothelium, these macrophages release further proinflammatory agents (eg, cytokines) that contribute to initiating the process of neointimal hyperplasia and subsequent restenosis. Moreover, a lower risk of arterial disruption and distal embolism, can be observed thanx to polytetrafluoroethylene coverage. However, BMS do not form this protective barrier and hence may be associated with a higher risk of restenosis [
77]. The available literature suggests that CS can be a favorable choice for stenting in CMI. These stents offer similar benefits as seen in other locations, and their specific features, such as high radial force, suitability for short lengths, precise deployment and minimal shortening upon expansion, make them well-suited for treating the common atherosclerotic, calcified lesions typically found at the mesenteric vessel orifice. It’s important to note that both balloon-expandable and self-expanding stents have complementary roles in CMI treatment. While balloon-expandable stents are preferred in most cases, self-expanding stents may be more appropriate in specific situations, such as longer lesions in the SMA beyond the orifice, managing intraluminal dissections resulting from initial endovascular techniques, and preserving significant collateral vessels, like those associated with a high take-off of a right hepatic artery [
5,
78,
79,
80].
Schoch et al. [
62] achieved 100% technical success in their mesenteric intervention study. They found a significant difference between stent types: among 77 patients with bare-metal stents (BMS), 52% required reintervention, while none of the 14 patients with covered stents (CS) needed reintervention (p < 0.05). CS also demonstrated significantly better patency than BMS (p < 0.04). However, the shorter follow-up for the CS group (mean 6.6 months) compared to the longer follow-up for the BMS group (mean 17 months) limits interpretation.
Girault et al. [
80] reported impressive patency rates for CS in SMA occlusive disease. At a 2-year follow-up, primary patency was 76%, primary-assisted patency was 95%, and secondary patency was 95%.
In the extensive study by Oderich et al. [
13], CS showed superiority over BMS in patients. CS-treated patients had higher rates of freedom from restenosis (92% vs. 53%; P = .003), symptom recurrence (92% vs. 50%; P = .003), and reintervention (91% vs. 56%; P = .005), along with better primary patency at 3 years (92% vs. 52%; P < .003). The subgroup requiring reintervention also had better outcomes with CS, including freedom from restenosis (89% vs. 49%; P < .04), symptom recurrence (100% vs. 64%; P = .001), and reintervention (100% vs. 72%; P = .03) at 1 year. Secondary patency rates were similar between both groups. Sénémaud et al. [
81] conducted a cohort study with 379 patients. Of the 37 patients who underwent the Retrograde Open Mesenteric Stenting (ROMS) procedure, 89% achieved technical success. The study reported in-hospital mortality of 27%, post-operative complications of 67%, and reintervention rate of 32%. After one year, estimated overall survival was 70.1%, with estimated freedom from re-intervention at 61.1%. Primary patency rate at one year was 84.54% and assisted primary patency rate was 92.4%.
Cirillo-Pen et al. [
82] performed ROMS on 34 patients with different types of mesenteric ischemia. The procedure achieved 91% technical success. Stent usage included CS in 58% of cases, extended CS with bare metal self-expanding stents in 6%, and BMS in 36%. Median follow-up was 3.7 years. At 1 year, freedom from reintervention was 87%, primary patency was 70%, primary-assisted patency was 87%, and secondary patency was 97%. Symptom recurrence was 95% at 1 and 3 years. The study did not evaluate stent type superiority. In an extensive study by AbuRahma et al. [
83] high initial success rates were observed in 83 patients BMS (97% technical and 96% clinical success). At a mean 31-month follow-up, the primary late clinical success rate was 59%, with an in-stent stenosis rate of 51% for stenosis ≥70%. Over 1 to 5 years, freedom from late recurrent symptoms ranged from 65% to 83%, and survival rates ranged from 51% to 88%. There were no significant differences in primary or assisted primary patency between stents in the SMA and CA. Goldman et al. [
84] studied 54 patients with CMI treated with BMS. Among them, 29.6% underwent intervention solely targeting the CA, while 70.4% received revascularization of the SMA with or without CA intervention. In the CA-only group, 50% experienced symptom recurrence, whereas in the SMA/CA-SMA group, 21.1% had recurrence. Patients without SMA intervention had a higher risk of symptomatic recurrence (HR: 3.2, 95% CI: 1.2-8.6, P = 0.016) and repeat intervention (HR: 5.5, 95% CI: 1.8-16.3, P = 0.001). The authors concluded that SMA revascularization is vital for achieving favorable symptom outcomes and reducing the need for repeat interventions. Rajaratnam et al. [
85] reported a 4% 30-day mortality rate in their study of 45 patients with CMI. Follow-up showed varying degrees of symptom resolution, with complete resolution in 65% of patients, partial improvement in 13%, no improvement in 22%, and symptom recurrence in 6%. Bulut et al. [
86] analyzed data from 141 patients with CMI treated with BMS, with a focus on the involvement of the CA and SMA. The occlusion rates were 10% for the CA and 30% for the SMA. The primary patency rates at 12 and 60 months were 77.0% and 45.0%, respectively, while the primary assisted patency rates were 90.3% and 69.8%. There were no significant differences in primary, primary assisted, and secondary patency between the CA and SMA cases.
Haben et al. [
76] studied 150 patients with CMI. Primary patency at 1 year was 86% for CA and 81% for SMA, while at 3 years it was 66% for CA and 69% for SMA. Increased age was associated with better results in the SMA. Chronic total occlusion in the SMA had worse patency, and younger patients had a higher proportion of SMA occlusion. Ostial flaring was associated with improved patency in the SMA. Authors concluded that bare-metal stents remain suitable for CMI treatment.
Awouters et al. [
87] retrospectively analyzed 76 CMI patients treated percutaneously. They found a 28.8% symptom relapse rate, with an average relapse time of 14.9 months over a mean 45.5-month follow-up. Cumulative incidence estimates showed relapse-free rates of 78.9%, 72.3%, and 70.3% at two, five, and ten years, respectively. Comparing circumferential and focal stenosis in the SMA, a trend towards longer relapse-free survival was observed in the circumferential group (78.2% vs. 55.5% at five years), although not statistically significant (P=0.063). Survival did not significantly differ between the groups (P = 0.64).
Altinas et al. [
88] investigated 245 patients who underwent endovascular intervention for CMI and acute-on-chronic mesenteric ischemia (AoCMI). The CMI group had higher one-year (85% vs 67%) and three-year (74% vs 54%) survival estimates compared to the AoCMI group. The presence of SMA stenosis, rather than occlusion, significantly improved the success of SMA recanalization in both CMI and AoCMI groups. Clinical improvement was reported in the majority of patients, and the median hospital stay was longer for the AoCMI group. Re-intervention within the first year occurred in 5.7% of patients, exclusively in the CMI group.
Overall, the data suggest that CS for SMA revascularization may offer advantages in terms of patency rates, freedom from reintervention, and symptomatic outcomes in CMI. However, further studies with larger sample sizes and longer follow-up durations are needed to confirm these findings and establish more definitive conclusions.
According to the ESVS [
64] routine mesenteric stenting is recommended for patients requiring endovascular treatment of CMI (Class I, Lev Evv B). However, there is ongoing controversy regarding the choice between BMS or CS for treating SMA stenosis. The Society for Vascular Surgery [
5] suggests the use of balloon-expandable covered intraluminal stents for treating the MAOD in CMI patients, with a Grade 2 (Weak) level of recommendation and a Quality of Evidence of C (Low). In the European guidelines for CMI [
55], the expert panel could not reach a consensus on recommending the use of CS due to current uncertainties regarding their superiority.
The results of two ongoing randomized controlled trials, the Dutch study (CoBaGi) including 6 centers (NCT02428582) [
89] and the French study (ESTIMEC) including 26 centers (NCT03586739) [
90] comparing CS and bare metal stents, are eagerly awaited.
Table 3 shows data from comparative studies between CS and BMS.
All the characteristics listed in the previous studies are summarized in
Table 4 and
Table 5.