Project description:ObjectivesA thrombus can occur in the stump of the pulmonary vein after left upper lobectomy, potentially causing postoperative cerebral infarction. This study aimed to verify the hypothesis that stagnation of blood flow inside the pulmonary vein stump causes thrombus formation.MethodsThe three-dimensional geometry of the pulmonary vein stump after left upper lobectomy was recreated using contrast-enhanced computed tomography. Blood flow velocity and wall shear stress (WSS) inside the pulmonary vein stump were analysed using the computational fluid dynamics (CFD) method and compared between the two groups (those with or without thrombus).ResultsThe volumes of average flow velocity per heartbeat < 10 mm/s, 3 mm/s, 1 mm/s (p-values 0.0096, 0.0016, 0.0014, respectively) and the volumes where flow velocity was always below the three cut-off values (p-values 0.019, 0.015, 0.017, respectively) were significantly larger in patients with a thrombus than in those without thrombus. The areas of average WSS per heartbeat < 0.1 Pa, 0.03 Pa, 0.01 Pa (p-values 0.0002, < 0.0001, 0.0002, respectively), and the areas where WSS was always below the three cut-off values (p-values 0.0088, 0.0041, 0.0014, respectively) were significantly larger in patients with thrombus than in those without thrombus.ConclusionsThe area of blood flow stagnation in the stump calculated by CFD method was significantly larger in patients with than in those without thrombus. This result elucidates that stagnation of blood flow promotes thrombus formation in the pulmonary vein stump in patients who undergo left upper lobectomy.
Project description:BackgroundPulmonary vein (PV) stump thrombus, a known source of cerebral infarction, develops almost exclusively after left upper lobectomy; however, the mechanism remains unclear. We therefore evaluated the hemodynamics in the left atrium with four-dimensional flow magnetic resonance imaging (4D-flow MRI), which enables the simultaneous depiction of blood flow at three locations and the evaluation of hemodynamics.Methods4D-flow MRI was basically performed 7 days after lobectomy for cancer arising in the right upper lobe (n=11), right lower lobe (n=8), left upper lobe (n=13), or left lower lobe (n=8). We evaluated dynamic blood movement from the ipsilateral remaining PV, the resected PV stump, and the contralateral PVs into the left atrium using 4D-flow MRI.ResultsThere were some characteristic blood flow patterns that seemed to either promote or prevent PV stump thrombus. Promotive flow patterns were significantly more frequent and preventive flow patterns were significantly less frequent in patients who had undergone left upper lobectomy than in those who had undergone other lobectomy. Accordingly, the degree of blood turbulence near the vein stump, as measured by the extent of change in the blood movement, was significantly higher in patients who had undergone left upper lobectomy than in patients who had undergone other lobectomy.ConclusionsOur study revealed that left upper lobectomy likely causes blood turbulence near the vein stump through complicated blood streams in the left atrium, which can play a part in the development of vein stump thrombus. Further study to identify patients at high risk of vein stump thrombus is warranted.
Project description:BackgroundA longer left superior pulmonary vein (LSPV) stump may increase the risk for postoperative cerebral infarction. Although the residual stump is generally longer after left upper lobectomy (LUL) than for other lobectomies, the length of the LSPV stump after LUL may be influenced by the anatomical relationship between the left atrial appendage (LAA) and the LSPV. Our aim in this study was to investigate the influence of this anatomical relationship on the residual length of the LSPV stump after LUL.MethodsThis was a retrospective analysis of 85 patients who underwent LUL at our institution, between January 2014 and March 2018. Based on pre-operative computed tomography (CT) images, the anatomical relationship between the LSPV and the LAA was classified into two patterns, namely an antero-superior and a postero-inferior pattern. The length of the LSPV stump for these two patterns was evaluated on postoperative CT images and compared between the two groups.ResultsOf the 85 patients, 49 were classified in the antero-superior pattern and 36 in the postero-inferior pattern. The mean length of the LSPV stump after LUL, overall, was 21.9 (range, 15-38) mm, with the stump being significantly longer for the antero-posterior (24.2 mm) than postero-inferior (18.9 mm) pattern.ConclusionsThe anatomical relationship between the LSPV and LAA, identified on pre-operative CT images, was associated with the length of the LSPV stump after LUL.
Project description:ObjectivesThe division of inferior pulmonary ligament (IPL) during upper lobectomy (UL) was believed to be mandatory to dilate the remaining lung sufficiently. However, the benefits, especially postoperative pulmonary function, remain controversial. This study aimed to evaluate whether IPL division leads to pulmonary dysfunction.MethodsThis retrospective study included 213 patients who underwent UL between 2005 and 2018. They were categorized into an IPL division group (D group, n = 106) and a preservation group (P group, n = 107). Postoperative dead space at the lung apex, pulmonary function and complications were assessed using chest X-rays and spirometry. Changes in bronchial angle, cross-sectional area and circumference of the narrowed bronchus on the excised side were measured on three-dimensional computed tomography.ResultsThere was no significant difference in the postoperative complication rate, the dead space area, forced vital capacity (FVC), or forced expiratory volume in 1 s (FEV1) between the 2 groups after right UL (FVC; P = 0.838, FEV1; P = 0.693). By contrast, after left UL pulmonary function was significantly better in the P than in the D group (FVC; P = 0.038, FEV1; P = 0.027). Changes in bronchial angle did not significantly differ between the 2 groups. The narrowed bronchus's cross-sectional area (P = 0.021) and circumference (P = 0.009) were significantly smaller in the D group than in the P group after left UL.ConclusionsIPL division during left UL caused postoperative pulmonary dysfunction and airflow limitation due to bronchial kinking. IPL preservation may have a beneficial impact on postoperative pulmonary function.
Project description:Pulmonary vein thrombosis (PVT) is a rare but life-threatening clinical condition, often found incidentally on imaging. In this report, we present an interesting case of PVT of the left inferior pulmonary vein with extension into the left atrium in a 78-year-old woman presenting with "jolts" in the chest. Initial imaging with plain chest film radiograph showed findings consistent with COPD and no acute intrathoracic process. A CT angiogram of the chest revealed a filling defect consistent with thrombus within the left inferior pulmonary vein extending into the left atrium. A transthoracic echocardiogram was remarkable for a severely enlarged right ventricular cavity with moderately reduced right ventricular systolic function and normal left ventricular size with preserved systolic function. She was not a candidate for any surgical interventions, and she was managed with systemic anticoagulation. Management of PVT mostly depends on the underlying cause as there are no well-defined treatment guidelines. The consensus recommends systemic anticoagulation until thrombus resolution. When anticoagulation is contraindicated, thrombectomy is indicated to restore blood flow. In patients with similar presentation and clinical history it is important to consider PVT, and to focus on prompt diagnosis and early initiation of appropriate treatment.