Successful Endovascular Treatment of Calcified Superior Mesenteric Artery Complicated by Intramural Hematoma in Chronic Mesenteric Ischemia

Background

Chronic mesenteric ischemia (CMI) is defined as ischemic symptoms caused by insufficient supply of blood to the gastrointestinal tract. Mesenteric ischemia is predominantly caused by atherosclerosis affecting the ostia of the superior mesenteric artery (SMA) [1]. Compared with open surgical bypass, endovascular therapy (EVT) has been associated with decreased morbidity and length of hospital stay [2]. Therefore, it has been generally accepted that EVT for SMA stenosis or occlusion provides excellent symptom relief in patients with CMI [3]. However, there is little information on the management of potential procedural complications during EVT for CMI [4,5].

Intramural hematoma can sometimes occur during cardiovascular intervention, and a possible mechanism is dissection into the media with extension into the medial space where blood has accumulated due to a distal dead end [6]. Since the intramural hematoma formation might be an important trigger of life-threatening sequelae, prompt management is crucial [7]. Herein, we describe a patient with CMI who underwent successful EVT for SMA despite a complicated intramural hematoma.

Case Report

A 70-year-old man was admitted to our hospital with recurrent abdominal pain, which had persisted for 3 months and worsened 1 month prior to admission. The patient had undergone hemodialysis for 30 years. Furthermore, he had been diagnosed as having a history of coronary artery disease and lower-extremity arterial disease. On admission, the patient had recurrent abdominal angina just after hemodialysis. Plain computed tomography showed calcification in the proximal celiac artery (Figure 1A) and SMA (Figure 1B), suggesting severe stenosis of the entrance of the intestinal arteries. There was no evidence of ileus or free air. At first, the patient’s symptoms appeared to become apparent because of volume reduction through hemodialysis in a patient exhibiting CMI; thus, we attempted to control the optimal dry weight. However, the recurrent abdominal pain during hemodialysis did not improve substantially, which indicated the need for revascularization. Given the lower risk of mobility and mortality in the endovascular intervention, EVT was indicated for the stenotic lesion of the SMA, with surgical back-up in the event of endovascular failure.

After achieving arterial access via the right common artery, a 5-Fr JR 4.0 diagnostic catheter was inserted into the SMA selectively. The angiogram showed significant stenosis in the proximal SMA (Figure 2A). At first, a 0.014-inch guidewire (Cruise; Asahi Intecc, Aich, Japan) was inserted into the SMA through a VISTA BRITE TIP JR 4.0-type guiding catheter (Cordis, Florida, USA). To obtain more detailed information regarding the vessel diameter and degree of calcification, we attempted intravascular ultrasound (IVUS) (Eagle Eye Platinum ST; Philips, Massachusetts, USA) using a catheter placed over a 0.014-inch guide wire. The IVUS catheter was then carefully advanced to the culprit lesion under fluoroscopic guidance and revealed severe stenosis with eccentric calcification in the proximal SMA (Figure 2A). To facilitate vessel expansion, a 6.0-mm cutting balloon (Boston Scientific, Massachusetts, USA) was inflated to 6 atm (Figure 2B). As a result, IVUS imaging revealed the dissection into the media with extension into the medial space without reentry and demonstrated a semilunar intramural hematoma (Figure 2C). In addition, cracks were also observed within the calcification with IVUS examination. To completely cover the hematoma, 2 self-expandable stents (SMART CONTOL stent 6.0/60 mm, 7.0/40 mm; Cordis, Florida, USA) were deployed and post-stent dilatation was performed. Acceptable stent expansion (Figure 2D) and good angiographic results were obtained (Figure 2E). The patient was discharged without complications and follow-up showed a good course without any abdominal angina. One year later, enhanced computed tomography showed that patency and flexibility of the 2 self-expandable stents were maintained (Figure 2F).

Discussion

As atherosclerosis is the most common cause of CMI, most patients have no symptoms and the development of CMI may take months or years to become clinically apparent [8]. However, patients diagnosed with advanced symptomatic CMI should be treated subsequently, as the transition from CMI to acute mesenteric ischemia can be unpredictable and lethal [9]. Although the prevalence of CMI remains unknown, patients undergoing hemodialysis who manifest more severe forms of cardiovascular disease have been associated with an increased incidence of CMI.

During the last few years, the number of mesenteric revascularizations has increased because of increasing recognition and the advent of EVT, which allows for a less invasive treatment [10]. Symptoms of mesenteric ischemia usually do not manifest until at least 2 of the 3 mesenteric arteries are significantly stenosed or occluded [11]. The role of 2-vessel stenting (of both the celiac artery and the SMA) remains controversial, but most reports indicate that angioplasty and stenting of a single vessel may be sufficient [12,13]. Treatment selection of the SMA in the present case included consideration of the vessel diameter, extent of stenosis, and degree of calcification.

Severely calcified vascular stenosis remains a challenge for EVT because of suboptimal vessel expansion and a higher rate of dissection [14]. For patients with mesenteric ischemia, stent under expansion has been reported as a major risk factor for stent restenosis [15]. Therefore, adequate plaque modification prior to stent implantation is critical for calcified lesions. The cutting balloon, which includes 3 or 4 radially directed micro-surgical metal blades on the balloon surface, has been used to create incisions in the calcified plaque and expand narrow lesions [16]. In the present case, inflation of the cutting balloon within the calcified lesion likely led to the dissection into the media with extension into the medial space without re-entry and the semilunar intramural hematoma. Remarkably, IVUS examination was useful in identifying the intramural hematoma. Moreover, we deployed the first stent at the distal dead end and the second stent at the entry point of the intramural hematoma under IVUS guidance. Therefore, IVUS examination also contributes to the treatment strategy for patients with CMI who underwent EVT. In endovascular for SMA, coaxial insertion of the guide catheter via the leg is difficult because the SMA branches sharply downward from the aorta [17]. Coaxial positioning of the catheter, via the arm, is essential to prevent potential catastrophic consequences of iatrogenic dissection.

The possible benefits of imaging follow-up after mesenteric revascularization are still unknown. A recent study reported that overall primary patency rates at 12 and 60 months were 77.0% and 45.0%, respectively, suggesting that close imaging and clinical surveillance allow for faster identification of patients with recurrent symptoms [18].

Conclusions

This case highlights the potential of EVT for heavy calcification of the SMA complicated by dissection without reentry. Intramural hematoma was observed with IVUS examination. We were able to contain the hematoma by implantation of self-expandable stents over the whole length of the SMA dissection under IVUS-guided EVT.