Smaller 8-mm diameter transjugular intrahepatic portosystemic shunts (TIPS) appear to be more beneficial than larger 10-mm TIPS stent-grafts, but lack the ability for secondary dilation in cases of clinical ineffectiveness. Underdilated VIATORR® TIPS stent grafts (VTS) expand passively, whereas novel VIATORR Controlled Expansion (VCX) stent grafts do not. This study evaluated the impact on survival of underdilated VCX compared with VTS in patients with decompensated cirrhosis.This was a prospective case-control study including patients with cirrhosis receiving TIPS using 10-mm VCX underdilated to 8 mm. Patients with cirrhosis receiving 10-mm VTS underdilated to 8 mm were matched for age, sex, indication for TIPS, and liver function.A total of 114 patients (47 VCX, 47 VTS, and 20 fully dilated VCX/VTS) were included. After TIPS implantation, underdilated VCX diameter was 8.0 (7.8-9.2) mm at a median time of 359 (87-450) days, compared with VTS at 9.9 (9.7-10.0) mm (p <0.001). The portosystemic pressure gradient immediately after TIPS procedure and after 7 days did not change significantly in VCX [mean 9.4 (± 0.8) vs. 10.4 (± 0.7) mmHg, p = 0.115). Hospital readmission rates for hepatic encephalopathy were 23% (n = 11) vs 51% (n = 24) for VCX and VTS (p <0.001), respectively. Patients with VCX had significantly lower rates of large-volume paracentesis (n = 5 [11%] vs. n = 10 [21%], p = 0.017) and heart failure (n = 1 [2%] vs. n = 7 [15%], p = 0.015). One-year mortality for underdilated VCX and VTS was 15% (n = 7) and 30% (n = 14) and, for fully dilated VCX/VTS, was 45% (n = 9) (log-rank p = 0.008), respectively.This study demonstrated that VCX stent grafts underdilated to 8 mm do not passively expand to nominal diameter and suggests reduced hospital readmissions because of hepatic encephalopathy, uncontrolled ascites, and heart failure, and improved 1-year survival compared with underdilated VTS.Transjugular intrahepatic portosystemic shunt (TIPS) improves survival in selected patients with liver cirrhosis and acute variceal bleeding or refractory ascites. Smaller 8-mm diameter TIPS stent grafts appear to improve patient outcome compared with larger 10-mm diameter stent grafts. Novel VIATORR® Controlled Expansion (VCX) stent grafts facilitate safe and stable underdilation to 8 mm of large 10-mm diameter stent grafts with improved patient outcome (survival, hepatic encephalopathy, ascites and heart failure) compared with legacy VIATORR TIPS stent graft (VTS). Thus, the use of underdilated VCX could preserve heart function.The study is registered at Clinicaltrials.govNCT03628807.