Impact of a Transplantation Critical Care Model on Short-Term Outcomes Following Liver Transplantation in High Acuity Patients: A Single-Center Experience

BACKGROUND

Orthotopic liver transplantation (OLT) is the definitive treatment for end-stage liver disease (ESLD). Patients with high acuity ESLD are frequently denied life-saving OLT by transplant centers due to reported inferior outcomes. We sought to analyze the impact of a specialized transplant critical care model (TCCM) on patient access to OLT and survival outcomes in high acuity patients.

METHODS

From January 2009 to December 2016, 122 adults were wait-listed at our transplant center with laboratory Model for ESLD ≥35 or Status I. Outcomes in Era I (prior to TCCM) were compared to Era II (TCCM established October 1, 2012).

RESULTS

Era II (TCCM) led to a significant increase in patients' access to OLT. Frequency and need to seek OLT at another center dropped 4-fold in Era II. Compared to Era I, the majority of patients in Era II required intensive care unit management (22% vs 83%, P < .01) and renal replacement therapy (11% vs 70%, P < .01) prior to OLT. Despite a higher acuity of illness in Era II, 1-year patient survival was comparable (89% Era I, 80% Era II, P = .35).

CONCLUSION

Implementation of a specialized TCCM expanded OLT access to high acuity patients, reduced the need to seek higher level of care elsewhere, and achieved excellent short-term post-transplant survival outcomes.

Ciliated hepatic cyst leading to squamous cell carcinoma of the liver - A case report and review of the literature

INTRODUCTION

Ciliated hepatic foregut cysts (CHFC) are rare, typically benign liver lesions. Primary squamous cell carcinoma (SCC) of the liver is also a rare entity with only approximately 25 reported cases in the literature. Recently, there have been four reports of malignant transformation of CHFC into primary squamous cell carcinoma of the liver. Here we report a fifth with unique presentation and review the literature.

PRESENTATION OF CASE

A 34 year-old man, with a history of ulcerative colitis, was incidentally found to have a 10 cm lesion in the right anterior sector plus left medial section of the liver on computerized tomography (CT) scan. The patient was asymptomatic at presentation and neoplastic markers were not elevated. Sequential transarterial chemoembolization (TACE) and portal vein embolization (PVE) allowed for left lateral section plus segment 1 hypertrophy and subsequent resection. Histology later revealed the cyst to be a CHFC and showed its malignant transformation. At 6 month follow-up, the patient has lung and abdominal recurrence.

DISCUSSION

With now the fifth case of malignant transformation of CHFC being reported, approximately 5% of all reported CHFC have undergone malignant transformation. This frequency, taken together with the aggressive disease course and poor prognosis, suggests that CHFC must not be presumed benign and should be regarded with clinical suspicion.

CONCLUSION

Accurate diagnosis of CHFC is mandatory given its potential malignant transformation. Even in asymptomatic CHFC, surgical excision is recommended. In addition, in cases of otherwise unresectable lesions, sequential TACE and PVE may provide optimal hypertrophy of future liver remnant.

Hepatitis C/HIV co-infection is associated with higher mortality in hospitalized patients with hepatitis C or HIV

Up to 10% of all patients with Hepatitis C virus (HCV) infection are co-infected with human immunodeficiency virus (HIV); 25-30% of HIV patients are co-infected with HCV. The aim of this study was to examine the association of HCV/HIV co-infection with outcomes of hospitalized patients compared to those with HCV or HIV monoinfection. Using the 2006 Nationwide Inpatient Sample, patients with HCV or HIV monoinfection or HCV/HIV co-infection were identified using ICD-9-CM codes. We compared liver-related and infection-related admission between the three groups of patients. Multivariate logistic regression was performed to identify independent predictors of in-hospital mortality. A total of 474,843 discharges with HCV monoinfection, 206,758 with HIV monoinfection and 56,304 with HCV/HIV co-infection were included. Liver-related admissions were more common in co-infected patients (15.4%) compared to those with HIV monoinfection (3.3%, P < 0.001). Primary infectious hospitalizations were more common in HIV monoinfection (33.9%) compared to co-infected patients (26%, P < 0.001). HCV/HIV co-infection was associated with higher mortality compared to HCV monoinfection (OR 1.41, 95% CI 1.20-1.65) but not when compared to monoinfected-HIV patients. HCV-associated cirrhosis or complications thereof conferred four times greater mortality risk in patients with HIV (OR 3.96, 95% CI 3.29-4.79). The rate of hospitalization for HCV/HIV co-infected patients (23.5%) was significantly higher than those with HCV (14.8%) or HIV (19.9%) (P < 0.001). HCV/HIV co-infection is associated with significantly higher rates of hospitalization and is a risk factor for in-hospital mortality compared to patients with isolated HCV.

Feasibility and safety of endoscopic evaluation of gastric emptying

BACKGROUND AND STUDY AIMS

Scintigraphy is the currently accepted method for evaluation of gastric emptying. Although quantitative, this method is complicated, time-consuming, and costly. If a simple endoscopic technique was available for those instances when quantification of an emptying abnormality is not needed, the same clinical information could be obtained in less time and with resource savings. Our aims in this study were therefore to assess the technical feasibility, tolerability, and safety of unsedated transnasal esophagogastroscopy (T-EG) as a technique for qualitative assessment of gastric emptying.

METHODS

The study was done in two phases. In the first phase, 18 volunteers (ten men, eight women) underwent T-EG at 4 hours, 5 hours, or 6 hours after ingestion of a standard meal used for scintigraphic evaluation of gastric emptying without radiolabeling. In the second phase, ten volunteers underwent T-EG after scintigraphic imaging had demonstrated complete gastric emptying.

RESULTS

Subjects in both phases tolerated the procedure well and completed the study. In the first phase, 13 of 15 volunteers exhibited complete gastric emptying at 6 hours (87%), while two (13%) revealed some particulate matter in the stomach at that time. In the second phase, one of the ten volunteers exhibited a small amount of solid food residue in the stomach despite documentation of scintigraphic complete emptying.

CONCLUSIONS

Evaluation of gastric emptying by unsedated T-EG is both feasible and safe. In healthy, asymptomatic individuals, complete gastric emptying of solid food may take as long as 6 hours.

High-dose vitamin E supplementation does not diminish ribavirin-associated haemolysis in hepatitis C treatment with combination standard alpha-interferon and ribavirin

BACKGROUND

Ribavirin is associated with haemolytic anaemia. Antioxidants have been reported to decrease severity of this anaemia.

AIM

To determine effect of vitamin E supplementation on ribavirin-associated haemolysis in chronic hepatitis C treated with standard alpha-interferon and ribavirin.

METHODS

Fifty-one naive chronic hepatitis C patients were randomized to receive either alpha-interferon/ribavirin therapy (control) or therapy plus vitamin E 800 IU b.d. with 24-week follow-up. Alanine aminotransferase ALT, haemoglobin and reticulocyte percentage were monitored. Symptoms and health-related quality of life were also monitored at each visit.

RESULTS

Forty-seven subjects were treated (27 vitamin E /20 controls). Thirteen withdrew because of adverse effects or non-compliance. Groups were similar in demographics, genotype and baseline lab indices. Comparison with baseline, treatment and follow-up values showed a significant haemoglobin and ALT reduction in both groups. There was no significant difference in haemoglobin and reticulocyte percentage between groups. Sustained viral response was not significantly different between vitamin E (11/18) and control (6/16) groups. Three patients required ribavirin dose-reduction in the vitamin E group compared with two controls. Health-related quality of life during and end-of-treatment was not different between groups.

CONCLUSIONS

Vitamin E supplementation alone during standard alpha-interferon and ribavirin therapy does not appear to diminish ribavirin-associated haemolysis.

Unsedated transnasal laryngo-esophagogastroduodenoscopy: an alternative to conventional endoscopy

The introduction, refinement, and subsequent widespread use of flexible fiberoptic endoscopes have revolutionized the diagnosis and management of upper gastrointestinal (GI) disorders. There has been a simultaneous increase in the cost of managing upper GI disorders, which is in part attributed to the high price of endoscopy. Unfortunately, in the current cost-conscious health-care environment, the high cost of endoscopy has resulted in the underuse of this valuable clinical tool. Unsedated transnasal laryngo-esophagogastroduodenoscopy (T-EGD) is a new technique for upper endoscopy that uses an ultrathin endoscope and has a comparable yield to conventional upper endoscopy but obviates the need for conscious sedation because it is better tolerated. Studies have found that T-EGD is a feasible alternative to conventional endoscopy in terms of safety, efficacy, and cost containment. This article reviews these factors, the technique of T-EGD, patient and endoscopist considerations, tissue sampling, and the characteristics of ultrathin endoscopes used for T-EGD.

Hepatitis C, cryoglobulinemia, and cutaneous vasculitis associated with unusual and serious manifestations

Hepatitis C viral infection is currently the leading cause of chronic hepatitis and cirrhosis. It also is a major predisposing factor for the development of hepatocellular carcinoma. It is estimated that approximately 1-2% of patients with hepatitis C infection have nonhepatic manifestations that are protean in nature. In this report, we describe six unusual cases of nonhepatic manifestations: abdominal vasculitis in two, peripheral neuropathy in two, and one patient each with central nervous system vasculitis and necrotizing cutaneous vasculitis. All patients had cutaneous vasculitis and cryoglobulinemia. None of our patients had cirrhosis, yet three of the six patients died. Because of the severe manifestations, aggressive therapy was instituted with interferon, immunosuppressive medications, i.v. immunoglobulin, and plasmapheresis. Our report underscores the importance of recognizing nonhepatic manifestations in patients with hepatitis C infection that may be associated with high morbidity and mortality.

Does open access endoscopy close the door to an adequately informed patient?

BACKGROUND

The use of open access endoscopy is increasing. Its effect on the adequacy of patient informed consent, procedure acceptance and the impact on subsequent communication/transfer of procedure results to the patient have not been evaluated. The aim of our study was to compare the extent of preknowledge of procedures and test explanation, patient medical complexity, information transfer and overall patient satisfaction between a patient group referred for outpatient open access endoscopy versus a patient group from a gastrointestinal (GI) subspecialty clinic.

METHODS

Information was obtained from all patients presenting for outpatient upper and lower endoscopy by using a 1-page questionnaire. Patients from the two groups who had an outpatient upper/lower endoscopic procedure were contacted by phone after the procedure to obtain information with a standardized questionnaire.

RESULTS

The open access patients reported receiving significantly less information to help them identify the procedure (p < 0.01) and less explanation concerning the nature of the procedure than the group of patients referred from the subspecialty clinic (p < 0.005). There was no difference between the two groups in satisfaction scores for examinations performed under conscious sedation. For flexible sigmoidoscopy without sedation, however, the GI clinic patient group were more satisfied with their procedure. The majority of patients, regardless of access, were more likely to receive endoscopic results from a gastroenterologist than the referring physician. Furthermore, the patients in the GI clinic group who underwent colonoscopy felt significantly better at follow-up.

CONCLUSIONS

Patients undergoing open access procedures are less likely to be properly informed about their endoscopic procedure. Our results indicate that with open access endoscopy, a defined mechanism needs to be in place for communication of endoscopic results to the patient.

Sigmoid stiffener for decompression tube placement in colonic pseudo-obstruction

BACKGROUND AND STUDY AIMS

Decompression tube placement improves outcome in colonic pseudo-obstruction (CP) which is refractory to conservative measures, especially if the decompression tube is placed proximal to the hepatic flexure. We evaluate the ability of a sigmoid stiffener to facilitate more proximal colonoscopy and decompression tube placement.

PATIENTS AND METHODS

A sigmoid stiffener is used in the standard fashion during colonoscopic decompression for pseudo-obstruction. After cecal wire placement, the colonoscope is withdrawn, leaving the stiffener and wire in place. By passing through the stiffener, an over-wire decompression tube can avoid sigmoid looping. We compared proximal extent of colonoscopy, tube position, endoscopy time, and patient outcomes using a sigmoid stiffener, with a control group of patients treated previously. Patients with colonic ischemia were excluded.

RESULTS

Using this technique, nine consecutive colonoscopies and decompression tube placements reached the right colon. Significantly, only three of seven control colonoscopies and two control decompression tubes did so. However, improvements in procedural time and patient outcome did not reach statistical significance. No complications occurred.

CONCLUSION

The use of a sigmoid stiffener during colonic decompression allows more proximal colonoscopy and decompression tube placement, with possible clinical benefit. We do not use this technique in the setting of left colon ischemia.

Biliary tract inflammatory disorders: primary sclerosing cholangitis and primary biliary cirrhosis

Primary sclerosing cholangitis (PSC) and primary biliary cirrhosis (PBC) are chronic progressive cholestatic diseases that frequently lead to biliary cirrhosis. The exact pathogenesis of these diseases remains elusive but is likely immunologically based. Complications range from fatigue and pruritus to end-stage liver disease. The risk of developing hepatocellular carcinoma is low for patients with PBC, whereas cholangiocarcinoma is common in PSC and carries an ominous prognosis. Although ursodeoxycholic acid is effective in slowing the progression of PBC, no effective medical therapy exists for PSC. Liver transplantation is the only option for patients with end-stage liver disease and yields excellent long-term survival in both groups.

Unsedated transnasal EGD: an alternative approach to conventional esophagogastroduodenoscopy for documenting Helicobacter pylori eradication

BACKGROUND

The aim of this study was to assess the yield of antral biopsies performed via unsedated transnasal esophagogastroduodenoscopy, a technique that does not require conscious sedation with its concomitant costs and complications, for documentation of Helicobacter pylori eradication.

METHODS

Nineteen patients who were previously CLO test positive on conventional esophagogastroduodenoscopy and subsequently treated for H pylori infection were enrolled. The subjects had not received antibiotic therapy in the prior month and had no prior gastric surgery. By using a GIF-N30 fiberoptic endoscope and a tiny cup biopsy forceps (1.8 mm diameter), unsedated transnasal endoscopy was performed and antral biopsy specimens were taken for a CLO test, histologic analysis (Dieterle stain), and tissue culture. On the same day, the subjects underwent a carbon 13-labeled area urea breath test. All subjects completed a visual analog scale, rating the acceptability of the unsedated transnasal examination and the previous sedated conventional esophagogastroduodenoscopy.

RESULTS

There was no statistically significant difference between the results of the CLO tests (5/19 positive) versus the 13C-urea breath test (4/19 positive) (p = 0.96), the CLO tests versus histologic findings (5/19 positive) (p = 0.71), or the 13C-urea breath test versus histologic findings (p = 0.96). All tissue culture results were negative. The overall acceptability of unsedated transnasal esophagogastroduodenoscopy was similar to that of sedated conventional esophagogastroduodenoscopy.

CONCLUSION

Unsedated transnasal esophagogastroduodenoscopy, a technique that eliminates the costs and complications associated with conscious sedation, is a feasible and accurate alternative to conventional esophagogastroduodenoscopy when documentation of H pylori eradication and confirmation of gastric ulcer healing are both indicated.

Effect of pharyngeal stimulation on the motor function of the esophagus and its sphincters

OBJECTIVE/HYPOTHESIS

Sensory impulses from the pharynx induce contraction of the upper esophageal sphincter (UES), relaxation of the lower esophageal sphincter (LES), and inhibition of peristalsis. To determine 1) the magnitude of UES contractile response to threshold volume of fluid that induces LES relaxation and 2) the effect of rapid pharyngeal air stimulation on LES resting pressure and its concurrent influence on the UES and progression of esophageal peristalsis.

METHODS

Eleven healthy volunteers (age, 31 +/- 2 y) were studied by concurrent UES, esophagealbody, and LES manometry.

RESULTS

At a threshold volume of 0.3 +/- 0.05 mL, injections of water into the pharynx directed posteriorly, resulted in complete LES relaxation. Duration of these relaxations averaged 19 +/- 1 seconds. In 10 of 11 subjects, these relaxations were accompanied by a simultaneous increase in UES resting tone that averaged 142% +/- 27% above preinjection values. Pharyngeal stimulation by rapid air injection resulted in complete LES relaxation in 8 of the 11 subjects (threshold volume, 14 +/- 6 mL). Five of 8 developed a concurrent mild increase in resting UES pressure (17% +/- 6% above preinjection values) (P < .05). Pharyngeal water injection inhibited the progression of the peristaltic pressure wave at all tested sites and in all subjects, but pharyngeal air injection in only 2 of the 11 studied subjects.

CONCLUSIONS

The inhibitory effect of pharyngeal water injection on LES resting pressure is accompanied by a substantial contractile effect on the UES. Although stimulation of the pharynx by rapid air injection may induce LES relaxation, its inhibitory effect on esophageal peristalsis and stimulatory effect on UES pressure are negligible compared with that of water injection.

Hepatocellular carcinoma after renal transplantation in the absence of cirrhosis or viral hepatitis: a case series

The occurrence of hepatocellular carcinoma (HCC) in renal transplant recipients has typically been associated with hepatitis B or C infection. We encountered two cases of HCC in renal transplant recipients with negative hepatitis B and C markers and no underlying liver pathology, in whom immunosuppression therapy consisted of prednisone and azathioprine (AZA). Patient no. 1 is a 66-year-old man with diabetes who underwent cadaveric renal transplantation 13 years before presentation. An ultrasound obtained for evaluation of a prolonged prothrombin time and decreased serum albumin level showed a suspicious nodular lesion in the left lobe of the liver. A computed tomographic (CT) scan confirmed a 4- x 5- x 5-cm mass that, on biopsy, was determined to be well-differentiated HCC. There was no evidence of metastasis, and the results of random biopsies of the surrounding parenchyma were normal. The patient underwent a left lateral segmentectomy, did well, and an initial alpha-fetoprotein (AFP) level of 85995 ng/mL decreased to 9 ng/mL. Approximately 20 months postoperatively, however, a surveillance CT scan showed three hypervascular lesions in the right lobe of the liver and the AFP level increased to 28,370 ng/mL. Subsequent percutaneous alcohol injections yielded good results, and the patient is alive and well 13 months later. Patient no. 2 is a 57-year-old man who underwent cadaveric renal transplantation 24 years earlier. A CT scan of the abdomen obtained for evaluation of lower abdominal pain showed a 4- x 4- x 6.5-cm mass in the right lobe of the liver that, on biopsy, was found to be poorly differentiated HCC. Multiple biopsies of adjacent liver parenchyma showed no evidence of cirrhosis, AFP level was normal, and imaging studies showed no evidence of tumor spread. The patient underwent a right hepatic lobectomy and is doing well without evidence of recurrence 27 months postoperatively. Our two patients had no evidence of viral hepatitis, cirrhosis, or metabolic liver disease, yet both developed HCC. The use of AZA may have had a role in the development of HCC. In renal transplant recipients on long-term immunosuppression therapy, particularly AZA, it is prudent to maintain a high index of suspicion for HCC when liver enzyme level or function abnormalities are encountered.

Diagnostic laparoscopy: an update

With new technical advances, wider availability, and the recent proliferation of less invasive surgery, the use of diagnostic laparoscopy has expanded far beyond its traditional role in the evaluation of chronic liver disease. Short of open laparotomy, diagnostic laparoscopy is the most accurate modality for staging of intra-abdominal malignancies, and is particularly well-suited for patients who otherwise would not require surgical palliation. In addition to avoiding unnecessary laparotomy in this group, diagnostic laparoscopy has proved valuable in the assessment of abdominal trauma, acute abdomen, and ischemic bowel disease. We briefly review here some of the new developments in the field of diagnostic laparoscopy.

Inhibition of resting lower esophageal sphincter pressure by pharyngeal water stimulation in humans

BACKGROUND/AIMS

Normal inhibition of lower esophageal sphincter (LES) tone occurs during swallowing and belching. However, it is known that it may occur independently of these functions. The aim of this study was to characterize the effect of pharyngeal water stimulation on resting LES pressure.

METHODS

The effect of rapid-pulse and slow continuous intrapharyngeal injection of minute increments of water on the resting tone of the upper and LES of 14 healthy young volunteers was evaluated by concurrent manometry, submental electromyography, and respirography.

RESULTS

At a threshold volume, pharyngeal water injection induced an isolated LES relaxation in all volunteers. The threshold volume inducing LES relaxation by rapid-pulse injection, 0.16 +/- 0.01 mL, was significantly lower than that with slow continuous injection (0.5 +/- 0.05 mL) (P < 0.05). The duration and magnitude of LES relaxation were not volume dependent. The duration of LES relaxation induced by rapid-pulse injection was significantly longer than that of swallows.

CONCLUSIONS

Minute amounts of liquid injected into the pharynx induce LES relaxation different from that of the normal swallow. Neither the duration nor the magnitude of this relaxation is volume dependent. Whereas the contribution of this finding to the mechanism of transient LES relaxation remains to be ascertained, it may partially explain the variability of the basal LES pressure.

Ultrasonic tissue characterization for diagnosis of acute myocardial infarction in the coronary care unit

The purpose of this study was to determine the use of ultrasonic tissue characterization (UTC) for the diagnosis of acute myocardial infarction (AMI). Real-time UTC and conventional 2-dimensional echocardiography were performed with a research prototype and commercially available ultrasonoscope, respectively, in 60 consecutive patients with suspected AMI. Diagnosis of AMI was documented by the presence of 2 of the 3 following clinical criteria: (1) typical history, (2) characteristic electrocardiographic changes, and (3) an increase in creatine phosphokinase-MB. Myocardial infarction was present in 24 of 60 patients and absent in 36 of 60 patients. Tissue characterization correctly diagnosed the presence of myocardial infarction in 22 of 24 patients and the absence in 33 of 36 patients. Two-dimensional echocardiography detected the presence of myocardial infarction in 21 of 24 patients and the absence in 34 of 36 patients. UTC had 2 false-negative and 3 false-positive studies, all in the region of apical infarcts. Two-dimensional echocardiography had 3 false-negative studies in patients with non-Q-wave myocardial infarction and 2 false-positive studies in patients with complete left bundle branch block. Both techniques had a comparable sensitivity, specificity, and accuracy.

Regional redistribution of myocardial perfusion by UL-FS 49, a selective bradycardic agent

The effects of UL-FS 49, a specific bradycardic agent, on systemic hemodynamics, regional myocardial function (sonomicrometry, percentage of segment shortening), and regional coronary blood flow (radioactive microspheres) were studied in open-chest, anesthetized dogs with severe left circumflex coronary artery (LCX) stenosis. UL-FS 49 was administered as two sequential bolus injections of 0.25 mg/kg. Heart rate decreased from 149 +/- 13 beats/min to 102 +/- 6 and 77 +/- 4 beats/min after 0.25 and 0.5 mg/kg cumulative doses of UL-FS 49, respectively. The reduction in heart rate was not associated with any significant change in left ventricular pressure or mean arterial pressure, left ventricular dp/dt, or coronary vascular resistance. Similarly no hemodynamic changes occurred with atrial pacing to the initial heart rate. Application of an LCX stenosis of sufficient severity to produce a 50% reduction in mean LCX blood flow (44 +/- 4 to 22 +/- 2 ml/min) resulted in a significant reduction in the percentage of segment shortening in the ischemic zone (9.8 +/- 1.6% to 6.5 +/- 1.1%). The percentage of segment shortening in the ischemic zone progressively improved to 8.4 +/- 1.2% and 9.4 +/- 0.5% after 0.25 and 0.5 mg/kg UL-FS 49, respectively. Subepicardial perfusion in the ischemic zone was decreased and subendocardial perfusion was increased after administration of UL-FS 49. Consequently the ischemic zone endocardial/epicardial ratio increased from 0.43 +/- 0.08 to 1.12 +/- 0.22 and 1.48 +/- 0.32 with low and high doses of UL-FS 49.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary artery fistula formation secondary to permanent pacemaker placement

We present the findings in two patients who apparently developed a coronary artery fistula as a complication of an endocardial pacing electrode. This complication may actually be occurring more frequently than recognized because the patient may be asymptomatic or minimally symptomatic and therefore not undergo a coronary angiogram. Awareness of this potentially serious complication is important and stresses the need for proper electrode placement without excess pressure on the tip.

Ultrasonic tissue characterization of normal and ischemic myocardium

Cardiac ultrasonic tissue characterization is designed to use the alterations in acoustic signals from the myocardium to differentiate normal from ischemic or infarcted tissue due to their characteristic backscatter attenuation. Various approaches such as use of a gray scale, color display, or quantitative image analysis have been used for tissue characterization, but all depend on subjective assessments and are not necessarily reproducible. The most promising method has been the use of "raw" radiofrequency signals and measure changes in the ultrasonic attenuation with an index of backscatter to distinguish normal from abnormal myocardium called "integrated backscatter" (IB). Various studies have demonstrated the changes in the ultrasonic backscatter with ischemia or infarction. In this review we summarize our experience with a research prototype instrument in tissue characterization and differentiation of normal, ischemic, infarcted, and post ischemic reperfused myocardium in anesthetized open chest dogs. Currently we are investigating the role of ultrasonic tissue characterization to estimate infarct size and plan to apply these observations to patients in order to detect viable myocardium and quantitate infarct size.

Doppler echocardiographic evaluation of left ventricular function

Invasive measurements of maximum acceleration of aortic blood flow are sensitive indicators of left ventricular function. Doppler echocardiography provides noninvasive measurements of aortic blood flow acceleration. Our studies establish the accuracy of Doppler-derived indices of aortic blood flow velocity for evaluation of left ventricular function. Doppler-derived peak velocity and mean acceleration showed excellent correlation with invasively measured peak left ventricular dP/dt and maximum aortic blood flow (dQ/dt) under varying heart rate, preload, afterload, and inotropic states. Similar correlations were observed between Doppler-derived peak velocity and mean acceleration and invasively measured left ventricular dP/dt and dQ/dt under conditions of varying degrees of myocardial ischemia. Thus, Doppler echocardiography provides an accurate noninvasive method to evaluate left ventricular performance.

Thyrotoxic periodic paralysis in a hispanic man

Thyrotoxic periodic paralysis occurs much more frequently in Orientals than in whites, and has rarely been reported in patients of Hispanic descent. A 28-year-old Mexican man presented with acute onset of bilateral lower extremity weakness after ingestion of a large carbohydrate meal. Laboratory investigation revealed severe hypokalemia, with a serum potassium level of 2.1 mmol/L (2.1 mEq/L), and hyperthyroidism. Administration of potassium chloride resulted in normalization of the serum potassium level and resolution of muscle weakness. Treatment with propranolol, and subsequent restoration of a euthyroid state with iodine 131, was effective in preventing further episodes of paralysis. Thyrotoxic periodic paralysis, although rare, may occur in Hispanic patients, and should be considered in the differential diagnosis of muscle weakness in this population.