Bifidobacteria metabolize lactulose to optimize gut metabolites and prevent systemic infection in patients with liver disease

Progression of chronic liver disease is precipitated by hepatocyte loss, inflammation and fibrosis. This process results in the loss of critical hepatic functions, increasing morbidity and the risk of infection. Medical interventions that treat complications of hepatic failure, including antibiotic administration for systemic infections and lactulose treatment for hepatic encephalopathy, can impact gut microbiome composition and metabolite production. Here, using shotgun metagenomic sequencing and targeted metabolomic analyses on 847 faecal samples from 262 patients with acute or chronic liver disease, we demonstrate that patients hospitalized for liver disease have reduced microbiome diversity and a paucity of bioactive metabolites, including short-chain fatty acids and bile acid derivatives, that impact immune defences and epithelial barrier integrity. We find that patients treated with the orally administered but non-absorbable disaccharide lactulose have increased densities of intestinal bifidobacteria and reduced incidence of systemic infections and mortality. Bifidobacteria metabolize lactulose, produce high concentrations of acetate and acidify the gut lumen in humans and mice, which, in combination, can reduce the growth of antibiotic-resistant bacteria such as vancomycin-resistant Enterococcus faecium in vitro. Our studies suggest that lactulose and bifidobacteria serve as a synbiotic to reduce rates of infection in patients with severe liver disease.

Liver Transplantation of HCV-viremic Donors Into HCV-negative Recipients in the United States: Increasing Frequency With Profound Geographic Variation

BACKGROUND

Direct-acting antiviral therapy made possible the novel practice of utilizing hepatitis C virus (HCV)-viremic (HCV RNA-positive) donors into HCV-negative recipients in the United States. Although initial reports of outcomes have been satisfactory, higher-quality longer-term outcomes remain to be elucidated.

METHODS

National data were examined from the Organ Procurement and Transplantation Network on adult patients in the United States who underwent a primary, single organ, deceased donor liver transplant from January 1, 2016 to March 31, 2020. Outcomes of HCV-negative recipients (R-) who received an allograft from donors who were HCV RNA-positive (D HCV+) donors were compared with HCV RNA-negative (D HCV-) donors.

RESULTS

There has been a 35-fold increase in D HCV+/R- liver transplants over the past 4 y in the United States, from 8 in 2016 to 280 in 2019. There was an almost 6-fold difference in this practice among UNOS geographic regions. Graft survival following D HCV+/R- liver transplantation was excellent, with 1-y rates being 91% and 90% and 2-y rates being 88.5% and 87% for D HCV+/R- and D HCV-/R-, respectively (P = 0.672). In multivariate analysis, adjusting for other donor and recipient attributes, D HCV+/R- was not associated with patient or graft survival.

CONCLUSIONS

The practice of D HCV+/R- continues to increase without discernible impact on medium-term outcomes. Notable geographic variation exists, suggesting inconsistent perceptions about the impact of D HCV+/R- transplantation on outcomes. These results strengthen the perceived safety in utilizing HCV-viremic donor organs as a donor pool expansion strategy, not only in the United States, but also worldwide.

Predictors of mortality and endoscopic intervention in patients with upper gastrointestinal bleeding in the intensive care unit

Background

The outcomes of patients undergoing esophagogastroduodenoscopy (EGD) in the intensive care unit (ICU) for upper gastrointestinal bleeding (UGIB) are not well described. Our aims were to determine predictors of 30-day mortality and endoscopic intervention, and assess the utility of existing clinical-prediction tools for UGIB in this population.

Methods

Patients hospitalized in an ICU between 2008 and 2015 who underwent EGD were identified using a validated, machine-learning algorithm. Logistic regression was used to determine factors associated with 30-day mortality and endoscopic intervention. Area under receiver-operating characteristics (AUROC) analysis was used to evaluate established UGIB scoring systems in predicting mortality and endoscopic intervention in patients who presented to the hospital with UGIB.

Results

A total of 606 patients underwent EGD for UGIB while admitted to an ICU. The median age of the cohort was 62 years and 55.9% were male. Multivariate analysis revealed that predictors associated with 30-day mortality included American Society of Anesthesiologists (ASA) class (odds ratio [OR] 4.1, 95% confidence interval [CI] 2.2-7.9), Charlson score (OR 1.2, 95% CI 1.0-1.3), and duration from hospital admission to EGD (OR 1.04, 95% CI 1.01-1.07). Rockall, Glasgow-Blatchford, and AIMS65 scores were poorly predictive of endoscopic intervention (AUROC: 0.521, 0.514, and 0.540, respectively) and in-hospital mortality (AUROC: 0.510, 0.568, and 0.506, respectively).

Conclusions

Predictors associated with 30-day mortality include ASA classification, Charlson score, and duration in the hospital prior to EGD. Existing risk tools are poorly predictive of clinical outcomes, which highlights the need for a more accurate risk-stratification tool to predict the benefit of intervention within the ICU population.

Workforce in hepatology: Update and a critical need for more information

The field of hepatology has experienced dramatic changes since the last workforce study in hepatology over 15 years ago. Hepatology practice has been dominated by hepatitis C but is now being overtaken by patients with nonalcoholic fatty liver disease. Expertise once attainable only through informal training, hepatology now has an accredited fellowship pathway and is recognized as a distinct discipline from gastroenterology with its own board certification. These changes that have occurred since the last workforce study in the prevalence and therapy of liver diseases and training may impact workforce needs. The time has come to conduct an updated analysis of the state of the hepatology workforce. The purpose of this article is to discuss the current issues facing training and workforce in hepatology and propose the next steps in conducting a workforce study. (Hepatology 2017;65:336-340).

Rifaximin Decreases the Incidence and Severity of Acute Kidney Injury and Hepatorenal Syndrome in Cirrhosis

BACKGROUND

While the effects of rifaximin have been shown to be protective against acute kidney injury (AKI) and hepatorenal syndrome (HRS) in alcohol-induced cirrhosis, its long-term effects on the renal function of other cirrhotic patients are unknown.

AIM

To examine the long-term effects of rifaximin on the renal function of patients with cirrhosis from various etiologies.

METHODS

In a retrospective study, we examined cirrhotic patients at the University of Chicago Liver Clinic from January 1, 2011, to December 31, 2014. The study enrolled patients on rifaximin for ≥90 days, who were then matched by age, gender, and MELD score to a control group. Patients with malignancy and renal replacement therapy (RRT) at baseline were excluded. Data were censored at the last follow-up, termination of rifaximin therapy, initiation of RRT, death, or liver transplant.

RESULTS

Eighty-eight rifaximin cases were identified and matched to 88 control cases. Baseline characteristics were similar, with the exceptions of more prevalent long-term midodrine use (≥90 days) (17.0 vs 4.5 %, p = 0.01) and baseline ascites (37.5 vs 23.8 %, p = 0.05) in the rifaximin group. There was no difference in the frequency of infections, deaths, liver transplants, or hospitalizations. After controlling for cofounders, the incidence rate ratio of AKI (IRR 0.71, p = 0.02) and HRS (IRR 0.21, p = 0.02), as well as the risk of requiring RRT (OR 0.23, p = 0.01), was lower in the rifaximin group.

CONCLUSIONS

Long-term use of rifaximin is associated with a decrease incidence of AKI and HRS and a decrease risk of requiring RRT in a general population of cirrhotic patients.

Novel educational interventions in residency increase knowledge of chronic liver disease and career interest in hepatology

There is an increasing burden of chronic liver disease (CLD) in the United States but a significant shortage of hepatologists. Thus, it is necessary to develop new recruitment strategies to the field of hepatology as well as ensure that non-gastroenterology-trained physicians are able to capably assist in the care of CLD. We established a novel, nonelective, inpatient hepatology rotation that uses required modules in the American Association for the Study of Liver Diseases Curriculum and Training-First Hepatitis B and C curriculums as well as in LiverLearning. A paper-based anonymous assessment was distributed to the inaugural 25 postgraduate years 2 and 3 internal medicine residents before and after the 2-week rotation over the course of 1 year. Both the prerotation and postrotation assessments included validated multiple-choice questions and Likert-type questions, which evaluated self-perceived knowledge and comfort with managing CLD. The mean comfort level (1 = not at all comfortable/strongly disagree, 5 = very comfortable/strongly agree) of managing several common liver diseases increased significantly after completion of the rotation (i.e., cirrhosis 2.8 versus 3.8, P < 0.001; hepatitis B 2.4 versus 3.4, P = 0.001; hepatitis C 2.6 versus 3.7, P = 0.002; nonalcoholic steatohepatitis 3.0 versus 4.0, P < 0.001; liver transplant care 2.1 versus 3.4, P < 0.001). There was also a significantly increased interest in hepatology as a career (2.6 versus 3.0, P = 0.03). Finally, the mean percentage of multiple-choice questions answered correctly on the pretest was 62% and posttest was 77% (P = 0.02).

CONCLUSION

Our novel curriculum and nonelective hepatology rotation has effectively demonstrated improvement in internal medicine residents' comfort with and knowledge of CLD, and increased career interest in hepatology was also observed after completion of the curriculum, which suggests that more exposure to CLD could positively impact recruitment to the workforce; larger, multicenter studies are needed to validate these results. (Hepatology 2016;64:2210-2218).

Randomized, double-blind, controlled study of glycerol phenylbutyrate in hepatic encephalopathy

Glycerol phenylbutyrate (GPB) lowers ammonia by providing an alternate pathway to urea for waste nitrogen excretion in the form of phenylacetyl glutamine, which is excreted in urine. This randomized, double-blind, placebo-controlled phase II trial enrolled 178 patients with cirrhosis, including 59 already taking rifaximin, who had experienced two or more hepatic encephalopathy (HE) events in the previous 6 months. The primary endpoint was the proportion of patients with HE events. Other endpoints included the time to first event, total number of events, HE hospitalizations, symptomatic days, and safety. GPB, at 6 mL orally twice-daily, significantly reduced the proportion of patients who experienced an HE event (21% versus 36%; P=0.02), time to first event (hazard ratio [HR]=0.56; P<0.05), as well as total events (35 versus 57; P=0.04), and was associated with fewer HE hospitalizations (13 versus 25; P=0.06). Among patients not on rifaximin at enrollment, GPB reduced the proportion of patients with an HE event (10% versus 32%; P<0.01), time to first event (HR=0.29; P<0.01), and total events (7 versus 31; P<0.01). Plasma ammonia was significantly lower in patients on GPB and correlated with HE events when measured either at baseline or during the study. A similar proportion of patients in the GPB (79%) and placebo groups (76%) experienced adverse events.

CONCLUSION

GPB reduced HE events as well as ammonia in patients with cirrhosis and HE and its safety profile was similar to placebo. The findings implicate ammonia in the pathogenesis of HE and suggest that GPB has therapeutic potential in this population. (Clinicaltrials.gov, NCT00999167).

The feasibility and advantages of billroth-I reconstruction in distal gastric cancers following resection

BACKGROUND

Gastric carcinomas are common malignancies in southern India and distal stomach remains the commonest site in low socio economic groups. Surgery still remains an important modality of treatment to achieve local control and also relieve obstructive symptoms. In this study we investigated the feasibility of performing a gastrectomy and billroth-1 type of anastomosis in a rural cancer center setting, with parameters like adequacy of margins, ease of anastomosis and its functional results were analysed.

MATERIALS AND METHODS

Eight patients presenting to a rurally based cancer center underwent a distal gastrectomy and billroth-1 type of anastomosis for continuity restoration.

RESULTS

All the patients had adequate proximal and distal marg. The surgical time varied between-hrs. The anastomosis was constructed without any tension on bowel ends in all patients. The average time to start oral feeds varied between- None of the patients showed symptoms of bile reflux nor dumping. The average hospital stay varied between.

CONCLUSIONS

Billroth-1 anastomosis is a physiologically more natural way of restoring continuity following a gastrectomy and it is a procedure which would be technically more simpler and decrease per and post operative complications and allow speedier post operative recovery following surgery on distal gastric cancers.

Multiphasic analysis of the temporal development of the distal gut microbiota in patients following ileal pouch anal anastomosis

BACKGROUND

The indigenous gut microbiota are thought to play a crucial role in the development and maintenance of the abnormal inflammatory responses that are the hallmark of inflammatory bowel disease. Direct tests of the role of the gut microbiome in these disorders are typically limited by the fact that sampling of the microbiota generally occurs once disease has become manifest. This limitation could potentially be circumvented by studying patients who undergo total proctocolectomy with ileal pouch anal anastomosis (IPAA) for the definitive treatment of ulcerative colitis. A subset of patients who undergo IPAA develops an inflammatory condition known as pouchitis, which is thought to mirror the pathogenesis of ulcerative colitis. Following the development of the microbiome of the pouch would allow characterization of the microbial community that predates the development of overt disease.

RESULTS

We monitored the development of the pouch microbiota in four patients who underwent IPAA. Mucosal and luminal samples were obtained prior to takedown of the diverting ileostomy and compared to samples obtained 2, 4 and 8 weeks after intestinal continuity had been restored. Through the combined analysis of 16S rRNA-encoding gene amplicons, targeted 16S amplification and microbial cultivation, we observed major changes in structure and function of the pouch microbiota following ileostomy. There is a relative increase in anaerobic microorganisms with the capacity for fermentation of complex carbohydrates, which corresponds to the physical stasis of intestinal contents in the ileal pouch. Compared to the microbiome structure encountered in the colonic mucosa of healthy individuals, the pouch microbial community in three of the four individuals was quite distinct. In the fourth patient, a community that was much like that seen in a healthy colon was established, and this patient also had the most benign clinical course of the four patients, without the development of pouchitis 2 years after IPAA.

CONCLUSIONS

The microbiota that inhabit the ileal-anal pouch of patients who undergo IPAA for treatment of ulcerative colitis demonstrate significant structural and functional changes related to the restoration of fecal flow. Our preliminary results suggest once the pouch has assumed the physiologic role previously played by the intact colon, the precise structure and function of the pouch microbiome, relative to a normal colonic microbiota, will determine if there is establishment of a stable, healthy mucosal environment or the reinitiation of the pathogenic cascade that results in intestinal inflammation.

Persistent spontaneous bacterial peritonitis: a common complication in patients with spontaneous bacterial peritonitis and a high score in the model for end-stage liver disease

OBJECTIVES

Spontaneous bacterial peritonitis (SBP) is associated with a high mortality rate. After antibiotic therapy, improvement in fluid polymorphonuclear (PMN) cell count is expected within 2 days. However, our institution recognized cases unresponsive to standard treatment.

METHODS

To study these recalcitrant cases, we completed a retrospective chart review of patients admitted for SBP to the University of Chicago from 2002 to 2007. SBP was defined by an ascitic PMN cell count ≥250/ml.

RESULTS

Of 55 patients with SBP, 15 did not show improvement in fluid PMN cell count to below 250/ml with standard treatment, leading to a prevalence of 27%. The patients with persistent SBP were younger than those with nonpersistent SBP [mean (SD) 51.80 (9.84) compared with 58.13 (8.79); p = 0.0253]. Persistent SBP had a higher serum ascites albumin gradient (SAAG) [median (Q1, Q3) 1.85 (1.50, 2.41) compared with 1.10 (0.60, 1.60)] and a higher score in the model for end-stage liver disease (MELD) [mean (SD) 27.98 (8.09) compared with 22.22 (8.10)] than nonpersistent SBP patients; p = 0.027 and p = 0.023, respectively. In addition, persistent SBP patients were more likely to have a positive ascitic fluid culture than nonpersistent SBP patients [odds ratio (OR) (95% CI) 4.33 (1.21, 15.47); p = 0.024]. Importantly, in-hospital mortality in the persistent SBP group was 40%, compared with 22.5% in the nonpersistent SBP group [OR = 2.30 (0.64, 8.19); p = 0.20].

CONCLUSIONS

The risk of persistent SBP is nearly 40% in patients with MELD score >25, SAAG >1.5 or positive ascitic fluid culture. Furthermore, patients who develop persistent SBP tend to experience a higher mortality rate. This study underscores the importance of further examination of this vulnerable population.

Impact of experience with a retrograde-viewing device on adenoma detection rates and withdrawal times during colonoscopy: the Third Eye Retroscope study group

BACKGROUND

Colonoscopy has been adopted as the preferred method to screen for colorectal neoplasia in the United States. However, lesions can be missed because of numerous factors, including location on the proximal aspect of folds or flexures, where they may be difficult to detect with the forward-viewing colonoscope. The Third Eye Retroscope (TER) is a disposable device that is passed through the instrument channel of a standard colonoscope to provide a retrograde view that complements the forward view of the colonoscope during withdrawal.

OBJECTIVE

To evaluate whether experience with the TER affects polyp detection rates and procedure times in experienced endoscopists who had not previously used the equipment.

DESIGN, SETTING, PATIENTS

This was an open-label, prospective, multicenter study at 9 U.S. sites, involving 298 patients presenting for colonoscopy, evaluating the use of the TER in combination with a standard colonoscope.

INTERVENTIONS

After cecal intubation, the TER was inserted through the instrument channel of the colonoscope. During withdrawal, the forward and retrograde video images were observed simultaneously on a wide-screen monitor.

MAIN OUTCOME MEASUREMENTS

Primary outcome measures were the number and size of adenomas and all polyps detected with the standard colonoscope and with the colonoscope combined with the TER. Secondary outcome measures were withdrawal phase time and total procedure time. Each endoscopist examined 20 subjects, divided into quartiles according to the order of their procedures, and results were compared among quartiles.

RESULTS

Overall, 182 polyps were detected with the colonoscope and 27 additional polyps with the TER, a 14.8% increase (P < .001). A total of 100 adenomas were detected with the colonoscope and 16 more with the TER, a 16.0% increase (P < .001). For procedures performed after each endoscopist had completed 15 procedures while using the TER, the mean additional detection rates with the TER were 17.0% for all polyps (P < .001) and 25.0% for adenomas (P < .001). For lesions 6 mm or larger, the overall additional detection rates with the TER for all polyps and for adenomas were 23.2% and 24.3%, respectively. For lesions 10 mm or larger, the overall additional detection rates with the TER for all polyps and for adenomas were 22.6% and 19.0%, respectively. The mean withdrawal times in the first and fourth quartiles were 10.6 and 9.2 minutes, respectively (P = .044).

LIMITATIONS

There was no randomization or separate control group. The endoscopists judged whether each lesion could have been detected with the colonscope alone by using their standard technique.

CONCLUSIONS

Polyp detection rates improved significantly with the TER, especially after 15 procedures, when the mean additional detection rate for adenomas was 25.0%. Additional detection rates with the TER for medium-size and large adenomas were greater than for smaller lesions. These results suggest that, compared with a colonoscope alone, a retrograde-viewing device can increase detection rates for clinically significant adenomas without detriment to procedure time or procedure complications. (

CLINICAL TRIAL REGISTRATION NUMBER

NCT00969124.).

Lack of Efficacy of Pegylated Interferon Monotherapy for Hepatitis C in Patients With End-Stage Renal Disease on Dialysis

Objectives To evaluate the efficacy, safety and tolerability of pegylated interferon monotherapy for chronic hepatitis C virus (HCV) in patients who are on dialysis. Methods From the University of Chicago Clinical Hepatology Database dated May 2001 to July 2005, 13 patients on dialysis with hepatitis C who have been treated with pegylated interferon were identified. Demographic and laboratory data were obtained from medical records. Patients received pegylated interferon alfa-2a at 135 µg subcutaneous (SQ) weekly (n = 8) or pegylated interferon alfa-2b at 1 µg/kg SQ weekly (n = 5). Side effects from the medication were noted. Results There were 7 men and 6 women, with a mean age of 54±11 years; 11 patients (85%) were African American and 11 patients (85%) were infected with HCV genotype 1. The median serum HCV RNA level was 3,273,000 copies/mL (range, 207,000 to >40,000,000), and the median serum alanine aminotransferase level was 29 IU/mL (range, 19-77). Four patients (30%) had bridging fibrosis or cirrhosis on liver biopsy. None of the 13 patients achieved sustained virologic response; 2 patients (15%) had an undetectable viral load at the end of therapy but relapsed within 6 months of follow-up. The most common side effects were fatigue (100%), anemia defined as 2 g/dL or greater drop in hemoglobin level (60%), and psychiatric symptoms (30%). Conclusions Pegylated interferon is ineffective for HCV infection in patients on dialysis. Furthermore, worsening anemia, which is usually prevalent at baseline in dialysis patients, is a common adverse event even in the absence of ribavirin use.

Evidence that selective endothelial dysfunction may occur in the absence of angiographic or ultrasound atherosclerosis in patients with risk factors for atherosclerosis

OBJECTIVES

The purpose of this study was to test the hypothesis that endothelial dysfunction occurs in humans before the development of structural coronary atherosclerosis when risk factors for this disease are present.

BACKGROUND

Animal studies have demonstrated that known risk factors for coronary atherosclerosis (hyperlipidemia, hypertension, diabetes) result in impaired endothelium-dependent vascular reactivity before the development of structural atherosclerosis. Previous studies in patients have been unable to distinguish early structural atherosclerotic disease from dysfunctional endothelium.

METHODS

Twenty-six patients with angiographically normal coronary arteries were studied at cardiac catheterization. The epicardial arteries were imaged using high resolution intravascular ultrasound to detect early structural changes and to determine changes in lumen size during pharmacologic provocation. A selective intracoronary Doppler velocity catheter was subsequently used to determine coronary blood flow velocity changes in response to the same pharmacologic provocation. Group I (9 patients) had no risk factors for atherosclerosis. Group II (17 patients) had one or more risk factors present.

RESULTS

Although both Groups I and II had a normal microvascular vasodilator response to adenosine or papaverine infusion (estimated coronary flow increase 396 +/- 200% vs. 326 +/- 161% [mean +/- SD], respectively, p = 0.103), only Group I patients had an intact response to acetylcholine infusion (378 +/- 203% vs. 75 +/- 93% in Group II, p = 0.001). Group II patients had an abnormal epicardial artery cross-sectional area vasoconstriction response to acetylcholine infusion (-16.6 +/- 12.4% [13 patients] vs. 1.3 +/- 11.5% in Group I, p = 0.0007). An additional four Group II patients had severe spasm during acetylcholine infusion. Epicardial vasodilator response to nitroglycerin infusion, however, was preserved in Group II (14.6 +/- 4.3% vs. 9.6 +/- 3.5% in Group I, p = 0.212). All Group I patients had normal vessels by intravascular ultrasound. Of the 17 patients in Group II, 7 had minimal disease on ultrasound (intimal thickening or small eccentric plaque) in the study vessel. These patients did not respond differently from the 10 Group II patients without demonstrable disease on ultrasound.

CONCLUSIONS

Patients with risk factors for coronary artery disease, normal coronary angiograms and no measurable disease by intracoronary ultrasound exhibit selective endothelial dysfunction at both the epicardial and microvascular levels. These findings may have implications for the treatment of "preclinical" coronary atherosclerosis.

Measurement by intracoronary ultrasound of in vivo arterial distensibility within atherosclerotic lesions

Arterial distensibility is diminished by atherosclerosis. This process has not been well studied in the coronary arteries. The purpose of this study was to assess changes in coronary arterial distensibility in 4 groups of patients. Group I (n = 20) consisted of patients with normal vessels, group II (n = 40) with diseased undilated vessels, group III (n = 15) after successful percutaneous transluminal coronary angioplasty (PTCA), and Group IV (n = 20) after successful directional coronary atherectomy (DCA). Intracoronary ultrasound imaging was used to assess distensibility, plaque morphology and atherosclerotic burden (expressed as the percentage of total vessel cross-sectional area occupied by plaque: percent plaque area). Distensibility was defined as percent change in lumen area in a cardiac cycle. Group I (normal vessels) had a distensibility = 14 +/- 5%, which was significantly greater than that seen in group II (distensibility = 4 +/- 2%, p < 0.001). In undilated vessels, distensibility was related to the degree of atherosclerotic burden (r = 0.75). This relation was curvilinear with a marked decrease in distensibility when percent plaque area exceeded 30%. Distensibility in group III (after PTCA) was higher than in group II (10 +/- 3 vs 4 +/- 2%, p < 0.001) despite a larger plaque burden (percent plaque area of 56 +/- 12 vs 46 +/- 11%, p < 0.005). The distensibility in group IV (after DCA) was also higher than in group II (8 +/- 4 vs 4 +/- 2%, p < 0.001) despite a similar residual percent plaque area (49 +/- 13 vs 46 +/- 11%, p = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Mechanisms of angiographically successful directional coronary atherectomy: evaluation by intracoronary ultrasound and comparison with transluminal coronary angioplasty

To assess the mechanisms of luminal improvement, 40 patients undergoing directional coronary atherectomy and a matched control group of 25 patients undergoing angioplasty were evaluated with intracoronary ultrasound imaging before and after intervention. Despite similar sized vessels, a similar angiographic severity of diameter stenosis (75 +/- 12% for the angioplasty group vs 69 +/- 15% for the atherectomy group, p = NS), and a similar plaque burden (percent plaque area) before intervention (84 +/- 5% in the angioplasty group vs 85 +/- 13% in the atherectomy group, p = NS), the residual plaque area after intervention was significantly smaller in the atherectomy group (54 +/- 14%) compared with the angioplasty group (65 +/- 13%, p = 0.002). Despite excellent angiographic results, significant residual plaque was noted after either successful intervention. Based on the absolute changes in lumen area, plaque area, and vessel area, improvement in the lumen area in the atherectomy group occurred as a result of plaque "compression" (48%), plaque removal (37%), and vessel expansion (15%). In the angioplasty group, plaque "compression" accounted for 94% of the improvement in lumen area, whereas vessel expansion contributed 6%. Thus "compression" of plaque remains the major mechanism of luminal improvement during atherectomy.

Intracoronary ultrasound imaging: correlation of plaque morphology with angiography, clinical syndrome and procedural results in patients undergoing coronary angioplasty

OBJECTIVES

This study was designed to establish the relation between ultrasound-derived atheroma morphology and the clinical, procedural and angiographic features of patients presenting for coronary angioplasty.

BACKGROUND

Intracoronary ultrasound imaging provides accurate dimensional information regarding arterial lumen and wall structures. Atheroma composition may also be assessed by ultrasound; however, only limited studies have been performed in patients.

METHODS

In 65 patients a diagnostic ultrasound imaging catheter or a combination imaging-angioplasty balloon catheter was used during coronary angioplasty to image both the lesion and the vessel segment just proximal to it (reference segment). Ultrasound images were analyzed for lumen, total vessel and plaque areas and were classified into five morphologic subtypes (soft, fibrous, calcific, mixed plaque and concentric subintimal thickening). These data were compared with angiographic morphologic features, procedural results and clinical angina pattern (stable vs. unstable).

RESULTS

Morphologic analysis of the ultrasound images obtained from the lesion correlated well with the clinical angina syndrome. Compared with patients with stable angina, patients with unstable angina had more soft lesions (74% vs. 41%), fewer calcified and mixed plaques (fibrotic, soft or calcific components in one or more combinations [25% vs. 59%]) and fewer intralesional calcium deposits (16% vs. 45%) (all p < 0.01). There was no correlation between ultrasound and angiographic lesion morphologic characteristics for either the reference segment or the lesion. Ultrasound demonstrated greater sensitivity than angiography for identifying unstable lesions (74% vs. 40%). Dimensional analysis demonstrated a large plaque burden in the reference segments (45 +/- 15% of total vessel area). Postangioplasty plaque burden was also high (62 +/- 9%). There was a significant, but only fair correlation between lumen area determined by angiography and ultrasound for both the reference segment (r = 0.70, p < 0.001) and the postangioplasty lesion (r = 0.63, p < 0.05).

CONCLUSIONS

Morphologic plaque classification by ultrasound is closely correlated to clinical angina but has little relation to established angiographic morphologic characteristics. Intracoronary ultrasound imaging during angioplasty identifies a large residual plaque burden in both the reference segment and the lesion. In the future, determination of plaque composition by intracoronary ultrasound may be important in selecting or modifying interventional therapeutic options.

Direct estimation of absolute glomerular filtration rate from dynamic renal scintigraphy using gamma camera

Absolute glomerular filtration rate (GFR), which can serve as a useful parameter of renal function, is not applied in clinical practice due to various technical constraints. We estimated GFR in 20 subjects (10 controls, 10 patients) by two different techniques simultaneously with a single intravenous injection of TC99m DTPA. The GFR results obtained by a conventional plasma clearance technique were compared with that of a simpler, scintigraphic technique which does not require any blood or urine sample, and these were found to correlate significantly (r = 0.75, p less than 0.001). The linear relationship between the fraction of the dose injected taken up by the kidneys during the parenchymal phase of the dynamic imaging study and the overall plasma clearance was also found to be significant (r = 0.932, p less than 0.001) our study shows that reliable estimation of absolute GFR is possible from the routine dynamic renal scinti-scanning procedure using the gamma camera - computer system, and hence might prove applicable in clinical practice.

Significance of transplant perfusion index in the diagnosis of acute rejection in live related renal allograft recipients

The study was undertaken to assess the usefulness of transplant perfusion index (TPI) in the differential diagnosis of renal allograft dysfunction with special reference to acute rejection. It was observed that the TPI has a sensitivity of 100 per cent and specificity of 98.1 per cent in the diagnosis of acute rejection. It was also observed that the serial values of TPI provided valuable clues and guide in the management of transplant dysfunction and helped in the immediate and long term follow-up of patients with renal allografts.

Serendipity in technetium-99m DTPA renal dynamic study

A nine-year-old child was referred for a routine renal dynamic study to detect a renal and/or renovascular cause for hypertension. Tc-99m DTPA renography accidentally discovered and correctly localized a pheochromocytoma.