Changes in renal artery resistance after meal-induced splanchnic vasodilatation in cirrhotic patients

Postprandial Changes in Gastrointestinal Hormones and Hemodynamics after Gastrectomy in Terms of Early Dumping Syndrome

Purpose

This study aimed to examine the early postprandial changes in gastrointestinal (GI) hormones and hemodynamics in terms of early dumping syndrome after gastrectomy for gastric cancer.

Materials and Methods

Forty patients who underwent gastrectomy for gastric cancer and 18 controls without previous abdominal surgery were enrolled. Before and 20 minutes after liquid meal ingestion, blood glucose, glucagon-like peptide-1 (GLP-1), and GLP-2 concentrations and superior mesenteric artery (SMA) and renal blood flow were measured. The patients' heart rates were recorded at 5-minute intervals. All subjects were examined for dumping syndrome using a questionnaire based on Sigstad's clinical diagnostic index.

Results

The postprandial increases in blood glucose, GLP-1, and GLP-2 levels as well as SMA blood flow and heart rate were greater in patients who underwent gastrectomy than in controls (all P<0.010). Patients who underwent gastrectomy showed a significantly decreased renal blood flow (P<0.001). Among patients who underwent gastrectomy, distal gastrectomy was a significant clinical factor associated with a lower risk of early dumping syndrome than total gastrectomy (hazard ratio, 0.092; 95% confidence interval, 0.013–0.649; P=0.017). Patients who underwent total gastrectomy showed a greater postprandial increase in blood glucose (P<0.001), GLP-1 (P=0.030), and GLP-2 (P=0.002) levels as well as and heart rate (P=0.013) compared to those who underwent distal gastrectomy.

Conclusions

Early postprandial changes in GI hormones and hemodynamics were greater in patients who underwent gastrectomy than in controls, especially after total gastrectomy, suggesting that these changes play a crucial role in the pathophysiology of early dumping syndrome.

Meal Ingestion and Hemodynamic Interactions Regarding Renal Blood Flow on Duplex Sonography: Potential Diagnostic Implications

Splanchnic blood flow changes dramatically after meal ingestion. The present study evaluated physiologic interactions between meal ingestion and hemodynamics with respect to renal blood flow on duplex sonography, assessing the possible influence on Doppler parameters used as diagnostic criteria for renal artery stenosis. Subjects comprised 26 healthy young men (mean age: 22 ± 2 y). Sonographic measurements were made shortly after breakfast and every 1 h thereafter and were compared with values measured before the meal. Peak systolic velocity in the renal artery was elevated post-prandially, peaking at 1 h (90 ± 12 cm/s), compared with pre-prandially (73 ± 10 cm/s, p < 0.01). Similarly, acceleration time at the intra-renal segmental artery shortened to a minimum at 1 h (45 ± 5 ms) compared with baseline (51 ± 6 ms, p < 0.01). The present study indicates that renal blood flow is altered for a few hours after meal ingestion. Attention should be paid to the interpretation of data measured after meals on duplex sonography for diagnosis of renal artery stenosis.

The role of Doppler sonography in predicting severity of acute pancreatitis

PURPOSE

To investigate the role of Doppler sonography (DUS) examination of major abdominal arteries in predicting severity of acute pancreatitis (AP).

METHODS

Twenty-nine patients diagnosed with AP and 14 controls were blindly and prospectively evaluated with Doppler sonography. Disease severity was defined clinically according to acute physiology and chronic health evaluation (APACHE II) score and was classified as severe for APACHE II score > or =8. DUS examination included the measurement of peak systolic velocity (PSV), end diastolic velocity (EDV), pulsatility index (PI), and resistance index (RI) of the celiac artery (CA) and superior mesenteric artery (SMA). Statistical analysis included Mann-Whitney U test, Student t test, and receiver operating characteristic curve analysis.

RESULTS

Twelve patients had severe AP and 17 had mild AP. PSV, EDV, and PI of the CA and RI of the SMA were higher in the severe AP group than in the mild AP and control groups (p < 0.001 and p < 0.0001, respectively). The sensitivity and specificity were 100% and 94%, respectively, for a 87 cm/second CA PSV cutoff value, 75% and 100%, respectively, for a 22 cm/second CA EDV cutoff value, 92% and 82%, respectively, for a 1.29 CA PI cutoff value, and 100% and 100%, respectively, for a 0.86 SMA RI cutoff value.

CONCLUSION

DUS can be useful in predicting the severity of AP in the early period of admission phase of the disease.

Renovascular Impedance Correlates with Portal Pressure in Patients with Liver Cirrhosis

PURPOSE

To prospectively evaluate, in patients with liver cirrhosis, the correlation between the renovascular impedance measured by using color flow and pulsed wave Doppler ultrasonography (US) and the portal pressure measured by using the hepatic venous pressure gradient (HVPG).

MATERIALS AND METHODS

The study was approved by the senior staff committee (comparable to institutional review board) of the university hospital, and written informed consent was obtained from all patients. Thirty-one patients with cirrhosis (22 men, nine women; mean age, 57.6 years +/- 8.8 [standard deviation]) and esophageal varices were consecutively enrolled in the study. Having fasted, the patients underwent color flow and pulsed wave Doppler US of the right interlobar renal artery (RRA) and the left interlobar renal artery (LRA). The resistance index (RI) and pulsatility index (PI) were determined. On the same day, with fluoroscopic guidance, a 5-F balloon-tipped catheter was advanced, via the right basilic vein, into the right hepatic vein; HVPG was calculated as the difference between the wedged and free hepatic pressures. All measurements were performed in triplicate, and permanent tracings were recorded. Correlations were made by using the Pearson test. The positive predictive value of renovascular impedance for detection of severe portal hypertension was determined.

RESULTS

Mean RI and PI values were 0.67 +/- 0.07 and 1.21 +/- 0.25, respectively, for the RRA, and 0.68 +/- 0.07 and 1.24 +/- 0.26, respectively, for the LRA. All patients had portal hypertension (mean HVPG, 19.3 mm Hg +/- 4.7; range, 11.5-33.5 mm Hg). Neither portal pressure nor renal impedance correlated with Child-Pugh score for cirrhosis. Renal artery impedance indexes correlated with the HVPG (for RRA RI: R = 0.424, P = .03; for RRA PI: R = 0.402, P = .04; for LRA RI: R = 0.352, P = .05; for LRA PI: R = 0.393, P = .02). A higher-than-normal renal impedance had a high positive predictive value (RRA RI and PI, 100%; LRA RI, 92%; LRA PI, 84%) for the detection of severe portal hypertension.

CONCLUSION

Renovascular impedance had a direct correlation with HVPG.