A case-control study of ultrasonographic determinants and 2D-Shearwave elastography changes of liver and spleen associated with non-malignant portal vein thrombosis in patients with decompensated cirrhosis

Abstract

Background and Aim: Portal vein thrombosis (PVT) due to portal flow stasis, complex thrombophilic disorders and factors leading to endothelial dysfunction, is an increasingly recognized complication in patients with cirrhosis. We tried to assess the Ultrasonography of Abdomen(USS) parameters and stiffness of liver and spleen as risk factors associated with non-malignant PVT in decompensated chronic liver disease patients(DCLD). Methods: We prospectively enrolled 502 patients with DCLD(CHILD B/C). All patients underwent detailed clinical evaluation, baseline investigation and ultrasonography. PVT was confirmed by CECT Abdomen in patients with USG evidence of PVT or alteration in portal flow dynamics. Liver and spleen stiffness(in kPa) were assessed by 2D Shear wave elastography (Supersonic Aixplorer). ROC was plotted to derive the best cut-off of parameters for development of PVT. Results: 39 patients were excluded. Of the 463 patients included, 51 had PVT (11%). It was observed that non-malignant PVT group patients had smaller liver size (11.8±1.8 vs 12.4±1.5, p=0.032), higher spleen size (14.9±2.3 vs 13.5±2.2, p<0.01), higher portal vein diameter(PVD, 14.4±3.2 vs 12.2±1.7,p<0.01), lower portal vein velocity(PVV,11.5±3.6 vs 16.7±3.6,p<0.01), higher liver stiffness(61.3±21.7 vs 55.2±17.1,p=0.02), higher splenic stiffness(50.3±15.1 vs 36.7±7.5,p<0.01) as compared to non-PVT group. On plotting ROC; PVV<12.5cm/sec (AUROC 0.86, sensitivity 74%, specificity 88%, NPV 95.9%)), PVD>13.7cm (AUROC 0.75), liver stiffness>66.5 kPa (AUROC 0.72), liver size<11.95cm(AUROC 0.63) were significantly associated with development of non-malignant PVT(p<0.01). On multiple logistic analysis PVD >13.75cm (B=1.21, OR:95%CI 3.36(1.05-10.7), p=0.04), PVV<12.5cm/sec (B= -1.06, OR:95%CI 0.35(0.13-0.09), p=0.03) were significant risk factors for PVT development in DCLD. Conclusion: The association of higher liver stiffness and smaller liver size as markers of extent of cirrhosis, higher splenic size and stiffness as a reflection of severity of portal hypertension, dilated PV and low PVV indicating sluggish portal flow that trigger thrombosis in the spleno-portal axis, were significantly associated with non-malignant PVT in DCLD.