Discussion
In this study, we evaluated the efficacy of high-dose barium therapy against rebleeding in a series of patients with CDB. Most cases were presumptive and had a history of CDB, and all cases had spontaneous cessation of initial bleeding. The barium therapy group showed a substantially lower incidence of rebleeding than the conservative therapy group, with a hazard ratio of 0.34. Furthermore, these patients had lower frequencies of rehospitalization, repeated blood transfusion, and colonoscopic reexamination, and a shorter length of hospitalization during long-term follow-up. These findings suggest that high-dose barium therapy may be effective in this hitherto difficult clinical condition.
The probability of rebleeding in this prospective cohort study was higher than in Western populations. Previous studies have shown low rebleeding ratios in Western populations, at 4% to 9% of patients at 1 year and 10% at 2 years, versus high ratios in Asians, at 20% to 35% at 1 year and 33% to 42% at 2 years. A rebleeding rate of 27% at 1 month was recently reported in Japan. Our present result is consistent with these Asian studies. The most likely explanation is related with differences in anatomical distribution patterns of diverticula, which are predominantly left-sided in the West and right-sided or bilateral in Asia.
Several case reports or case series of barium impaction therapy for severe CDB have been reported. Adams demonstrated for the first time that 26 of the 28 massive bleeding episodes were resolved by barium impaction therapy, and that this treatment avoided emergency colectomy in 3 patients. In addition, Koperna et al reported failure rates of conservative therapy and barium therapy with subsequent rebleeding of 43.4% and 15.9%, respectively, and suggested that complications and mortality after surgery were higher than those after barium therapy. The goal of intervention in CDB is to identify SRH. However, the rate of SRH identification varies widely, from 7.7% to 43% of LGIB cases, because the colon has an anatomically large and complex surface area, often with multiple potential sources, and because bleeding tends to be intermittent in nature. Most diagnoses of CDB are therefore presumptive, accounting for as many as 87% of LGIB cases. Moreover, even when SRH is identified and treated, some patients with multiple diverticula will bleed again from another diverticulum. We consider that this clinical picture supports the indication of barium impaction therapy for presumptive CDB, particularly with multiple diverticula (Fig. 4). Previous reports have also suggested that barium impaction therapy has advantages in patients at risk for surgery or angiography; in patients with uncontrolled bleeding because of therapeutic procedures or uncontrolled presumptive CDB; as well as in patients unable to receive 4 to 6 L of bowel preparation or with multiple or inaccessible lesions. Concerns have been raised that retained barium would preclude accurate colonoscopic visualization of rebleeding cases. However, colonoscopy with full preparation in our present cases did not interfere with visualization of the bowel lumen.
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Figure 4.
Flow chart for the management of colonic diverticular bleeding. When patients are hospitalized for severe or continuous bleeding suspected from colonic diverticula, most cases resolve without procedures. Urgent or elective colonoscopy with or without other modalities is indicated in accordance with the general condition of the patient as well as in consideration of institutional and national background. However, stigmata of hemorrhage is infrequently identified, and thus many bleeding cases given a final diagnosis of diverticulosis will have a presumptive rather than definite diagnosis. Definite diagnosis should be managed by endoscopic therapy initially in the conventional manner, possibly with the option of adding high-dose barium impaction therapy in particularly patients with multiple diverticula, whereas presumptive cases have the additional option of barium impaction therapy to prevent further rebleeding.
The fundamental mechanism of the effect of barium enema is unknown, but 3 factors can be considered: (1) tamponade of the bleeding vessel through physical pressure caused by the barium solution, (2) a direct hemostatic effect of barium sulfate, and (3) protection from intestinal fluids through the long-term presence of barium in the diverticula. Barium enema administered from 3 ft (91 cm) above the examination table produces an estimated intraluminal colonic pressure of 80 mm Hg, which is considered safe, whereas administration from 6 ft (1.8 m) produces 140 to 168 mm Hg, which can result in perforation. The source of CDB is thought to be arterial, which would produce a mean arterial pressure of about 90 mm Hg. We therefore administered barium from 3 to 4 ft above the table, equivalent to an intraluminal colonic pressure of 90 mm Hg, and this might therefore have been effective in stopping the arterial bleeding. During barium coagulation, a tap water enema is reportedly better than most barium suspensions as it contains no anticoagulants and is more effective in clot formation. Moreover, use of a high concentration of barium and retention in the colon may be related to increased viscosity and the facilitation of coagulation. Accordingly, we used 200 w/v percentage barium sulfate with tap water in the present study. Finally, previous studies have shown that barium in the colonic diverticula or appendix can be retained without inflammation for several months, and sometimes years, suggesting that barium impaction is effective in preventing rebleeding as well as safe. Moreover, long-term impaction with barium may protect diverticula from the adverse impact of colonic microflora in the development and progression of diverticular disease.
This study experienced no severe complications from barium impaction therapy, suggesting the safety of barium enema of the colon. Nevertheless, complications have been reported. These include perforation, trauma from the enema tip or retention balloon, mucosal irritation, and thrombosis of the involved vessels. Of these, colonic perforation is the most frequent, occurring in approximately 0.04% of patients. Contrasting with this, patients undergoing endoscopy are also at risk of perforation, particularly those with colonic diverticula. Thus, both forms of CDB examination should be carried out carefully.
This study has several limitations. First, it was conducted in a non–double-blinded manner because of the difficulty in producing a suitable barium replacement. Although this might have biased the secondary outcomes, it is unlikely to have influenced rebleeding. Second, although we adjusted the multivariate analysis for hypertension, NSAIDs, and chronic renal failure, the number of patients with rebleeding was too small to allow adjustment for other risk factors. Third, although we formulated precise diagnostic criteria for CDB, the number of patients who underwent urgent colonoscopy was small (n = 6), which likely resulted in a low detection rate of SRH. Nevertheless, the groups did not significantly differ in urgent colonoscopy rate.