Validation of MRI assessment of foot perfusion for improving treatment of patients with peripheral artery disease.

INTRODUCTION: Information on tissue perfusion in the foot is important when treating patients with chronic limb-threatening ischemia. This study aims to test the reliability of different magnetic resonance sequences when measuring perfusion in the foot. METHODS: Sixteen healthy volunteers had their right foot scanned in a test/retest study with six different magnetic resonance sequences (BOLD, multi-echo gradient echo (mGRE), 2D and 3D pCASL, PASL FAIR, and DWI with intravoxel incoherent motion (IVIM) with quantitative measurements of perfusion. For five sequences, cuff-induced ischemia followed by a hyperactive response was measured. Images of the feet were segmented into angiosomes and perfusion data were extracted from the five angiosomes. RESULTS: BOLD, PASL FAIR, mGRE, and DWI with IVIM had low mean differences between the first and second scans, while the results of 2D and 3D pCASL had the highest differences. Based on a paired t-test, BOLD, and FAIR were able to distinguish between perfusion and no perfusion in all angiosomes with p-values below 0.01. This was not the case with 2D and 3D pCASL with p-values above 0.05 in all angiosomes. The mGRE could not distinguish between perfusion and no perfusion in the lateral side of the foot. CONCLUSION: BOLD, mGRE, pASL FAIR, and DWI with IVIM seem to give more robust results compared to 2D and 3D pCASL. Further studies on patients with peripheral artery disease should explore if the sequences can have clinical relevance when assessing tissue ischemia and results of revascularization. IMPLICATIONS FOR PRACTICE: This study provides knowledge that could be used to improve the diagnosis of patient with chronic limb-threatening ischemia to explore tissue perfusion.

Reoperation after antireflux surgery: a population-based cohort study.

BACKGROUND: Antireflux surgery for gastro-oesophageal reflux disease (GORD) and/or hiatal hernia is effective. Between 10 and 20 per cent of patients undergo reoperation for recurrent symptoms. Most studies are undertaken in a single centre and possibly underestimate the rate of reoperation. The aim of this nationwide population-based cohort study was to investigate long-term reoperation rates after antireflux surgery. METHODS: This study included patients who underwent antireflux surgery between 2000 and 2017 in Denmark, and were registered in the Danish nationwide health registries. Reoperation rates were calculated for 1, 5, 10 and 15 years after the primary antireflux operation for GORD and/or hiatal hernia. Duration of hospital stay, 30- and 90-day mortality and morbidity, and use of endoscopic pneumatic dilatation were assessed. RESULTS: This study included a total of 4258 antireflux procedures performed in 3717 patients. Some 3252 patients had only primary antireflux surgery and 465 patients underwent reoperation. The 1-, 5-, 10- and 15-year rates of repeat antireflux surgery were 3·1, 9·3, 11·7 and 12·8 per cent respectively. Thirty- and 90-day mortality rates were similar for primary surgery (0·4 and 0·6 per cent respectively) and reoperations. The complication rate was higher for repeat antireflux surgery (7·0 and 8·3 per cent at 30 and 90 days respectively) than primary operation (3·4 and 4·8 per cent). A total of 391 patients (10·5 per cent of all patients) underwent endoscopic dilatation after primary antireflux surgery, of whom 95 (24·3 per cent) had repeat antireflux surgery. CONCLUSION: In this population-based study in Denmark, the reoperation rate 15 years after antireflux surgery was 12·8 per cent. Reoperations were associated with more complications.

ANTECEDENTES: La cirugía antirreflujo es efectiva en el tratamiento de la enfermedad por reflujo gastroesofágico (gastro-oesophageal reflux disease, GORD) y/o de la hernia de hiato. Entre el 10% y el 20% de los pacientes tienen que ser reoperados por recidiva de los síntomas. La mayoría de los estudios son unicéntricos, lo que posiblemente infravalora la tasa de reintervenciones. El objetivo de este estudio de cohortes de base poblacional nacional fue investigar las tasas de reintervenciones a largo plazo tras la cirugía antirreflujo. MÉTODOS: Este estudio incluyó pacientes sometidos a cirugía antirreflujo entre 2000 y 2017 en Dinamarca y que fueron registrados en los registros nacionales de salud daneses. Se calcularon las tasas de reintervención para 1, 5, 10 y 15 años tras la operación antirreflujo primaria por GORD y/o hernia de hiato. Se evaluaron la duración de la estancia hospitalaria, la morbilidad y mortalidad a 30 y 90 días, y el uso de dilatación neumática endoscópica. RESULTADOS: Este estudio incluyó un total de 4.258 procedimientos antirreflujo efectuados en 3.717 pacientes. Unos 3.252 pacientes fueron sometidos únicamente a cirugía antirreflujo primaria y 465 pacientes a una reintervención. Las tasas de cirugía antirreflujo de revisión a 1, 5, 10 y 15 años fueron del 3,1%, 9,3%, 11,7% y 12,9%, respectivamente. La mortalidad a los 30 y 90 días fue similar cuando se comparó cirugía primaria y reintervenciones (mortalidad a 30 días 0,4% y 90 días 0,6% versus 0% y 0,4%, respectivamente). La tasa de complicaciones fue más elevada para la cirugía antirreflujo de revisión en comparación con la cirugía primaria: tasa de complicaciones a los 30 días 7,0%, 90 días 8,3% versus 30 días 3,4% y 90 días 4,8%, respectivamente. Un total de 391 pacientes (10,5% de todos los pacientes) fueron sometidos a dilatación endoscópica tras la cirugía antirreflujo primaria y 95 de 391 pacientes (24,3%) precisaron cirugía antirreflujo de revisión. CONCLUSIÓN: En este estudio de base poblacional en Dinamarca, la tasa de reintervención a los 15 años tras cirugía antirreflujo fue del 12,9%. Las reintervenciones se asociaron con más complicaciones.

Where to place the Doppler sample volume in the human main pulmonary artery: evaluated from magnetic resonance phase velocity maps.

OBJECTIVE: To give recommendations for the placement of Doppler sample volumes for blood flow assessment in the human main pulmonary artery. METHODS: In 10 healthy volunteers MR-phase velocity measurements were obtained and computing of the mean temporal blood velocity data was performed to guide single point Doppler velocity recordings. RESULTS: The mean temporal blood velocity profiles were consistently skewed with the lowest blood velocities towards the inferior/right vessel wall. Blood velocity indices (ratio of point to mean velocities, where a point equals a square of 4 pixels) varied considerably with the lowest indices located towards the inferior/right vessel wall. A centrally located fictive sample volume revealed an average blood velocity index value (average of all 10 subjects) of 1.08 (range 0.99-1.25; s.d. 0.08) where the central point was defined at maximum systole, and a value of 1.13 (range 0.97-1.34; s.d. 0.11) when the central point was defined in end-diastole. The mean of multiple sample volumes along the inferior/right to superior/left diameter revealed a blood velocity index of 1.01 (range 0.87-1.21; s.d. 0.09) in systole and 1.03 (range 0.87-1.19; s.d. 0.09) in diastole. CONCLUSIONS: For practical clinical purposes, single point estimation of the mean blood velocity in the pulmonary artery should be performed centrally. The use of multiple sample volumes placed along the inferior/right to superior/left diameter improves the mean velocity estimate in healthy volunteers. Further studies should be conducted to reinforce the basis for Doppler velocity recording in the diseased human pulmonary artery as well as to investigate other important determinants of Doppler-derived CO, namely angle of insonation and assessment of the cross-sectional area.

The impact of ischemic heart disease on main pulmonary artery blood flow patterns: a comparison between magnetic resonance phase velocity mapping and transesophageal color Doppler.

OBJECTIVE: To give a detailed evaluation on main pulmonary artery blood velocity patterns, in patients with ischemic heart disease and to provide recommendations for pulsed Doppler sample volume placement, in order to optimize cardiac output estimation. METHODS: Using magnetic resonance phase and esophageal color Doppler velocity mapping in 12 patients with ischemic heart disease and undergoing coronary artery by-pass grafting, very similar data on pulmonary artery blood velocity patterns were provided for comparison with each other. RESULTS: Peak blood velocities were located in the inferior half of the main pulmonary artery cross-sectional area. Early after peak systole the highest velocities shifted towards the superior/left (major curvature) with a simultaneous decrease in velocities inferiorly. The velocity decrease further evolved into retrograde flow to the inferior/right (minor curvature). This feature was significantly enhanced compared to earlier findings in healthy volunteers. The mean temporal blood velocity profiles were asymmetrically skewed, thereby giving unreliable cardiac output estimates based on single point Doppler blood velocity recordings. The error incurred may amount to more than 100% in extreme cases. According to our data, optimal assessment of cardiac output should be based on multiple sample volumes placed along the inferior/right to superior/left diameter. CONCLUSIONS: MR-phase velocity mapping and multiplane transesophageal color Doppler recordings provided similar blood velocity patterns in patients with ischemic heart disease. The skewness of the mean temporal blood velocity profile is enhanced compared with healthy subjects, resulting in error in the assessment of CO by means of pulsed Doppler echocardiography. By using multiple Doppler sample volumes, the error can be minimized.

Three-dimensional visualization of velocity profiles in the human main pulmonary artery with magnetic resonance phase-velocity mapping.

Detailed data on blood velocity fields in the normal human main pulmonary artery are an essential platform for discriminating physiologic from pathologic pulmonary flow patterns. Over the years, many studies have revealed quite inconsistent data mainly because of lack of suitable measuring techniques. By using combined cardiac- and respiratory-triggered magnetic resonance phase velocity mapping, very consistent data were obtained in 12 volunteers. In all subjects the location of the highest axial velocities was shifted from the inferior-right toward the superior-left part of the vessel area during the right ventricular contraction, with rapidly decreasing velocities to the inferior right evolving into retrograde flow in the deceleration phase. The mean temporal velocity profile was consistently skewed with a low flow region also toward the inferior-right vessel wall. The magnetic resonance phase shift method used in this study provided remarkably consistent high-quality data about human pulmonary artery velocity fields. This is most likely because of the use of combined cardiac and respiratory triggering.