Pulmonary hypertension impairs vasomotor function in rat diaphragm arterioles.

Pulmonary hypertension (PH) is a chronic, progressive condition in which respiratory muscle dysfunction is a primary contributor to exercise intolerance and dyspnea in patients. Contractile function, blood flow distribution, and the hyperemic response are altered in the diaphragm with PH, and we sought to determine whether this may be attributed, in part, to impaired vasoreactivity of the resistance vasculature. We hypothesized that there would be blunted endothelium-dependent vasodilation and impaired myogenic responsiveness in arterioles from the diaphragm of PH rats. Female Sprague-Dawley rats were randomized into healthy control (HC, n = 9) and monocrotaline-induced PH rats (MCT, n = 9). Endothelium-dependent and -independent vasodilation and myogenic responses were assessed in first-order arterioles (1As) from the medial costal diaphragm in vitro. There was a significant reduction in endothelium-dependent (via acetylcholine; HC, 78 ± 15% vs. MCT, 47 ± 17%; P < 0.05) and -independent (via sodium nitroprusside; HC, 89 ± 10% vs. MCT, 66 ± 10%; P < 0.05) vasodilation in 1As from MCT rats. MCT-induced PH also diminished myogenic constriction (P < 0.05) but did not alter passive pressure responses. The diaphragmatic weakness, impaired hyperemia, and blood flow redistribution associated with PH may be due, in part, to diaphragm vascular dysfunction and thus compromised oxygen delivery which occurs through both endothelium-dependent and -independent mechanisms.

Diaphragmatic weakness after transcatheter arterial chemoembolization of the right inferior phrenic artery for treatment of hepatocellular carcinoma: a comparison of outcomes after N-butyl cyanoacrylate versus gelatin sponge embolization.

BACKGROUND: The inferior phrenic artery (IPA) is the most common extrahepatic feeder for hepatocellular carcinoma (HCC) during transhepatic arterial chemoembolization (TACE). PURPOSE: To compare the incidence of diaphragmatic weakness in patients with HCC after TACE of the right IPA conducted using either N-butyl cyanoacrylate (NBCA) or gelatin sponge particles. MATERIAL AND METHODS: Medical records of 111 patients who underwent TACE of the right IPA using NBCA were retrospectively reviewed and compared with data from 135 patients with IPA embolization using gelatin sponge particles. RESULTS: The incidence of diaphragmatic weakness after the initial TACE procedure did not significantly differ between the groups (NBCA group 16.2%; gelatin sponge group 20.7%; P = 0.458). Five patients in the NBCA group and 11 in the gelatin sponge group showed spontaneous resolution of diaphragmatic weakness after a mean period of 3.5 months. Diaphragmatic weakness developed after the initial follow-up visit in 17 patients from the gelatin sponge group due to repeated TACE of the right IPA (mean 2.4 sessions; range 2-4 sessions), while it spontaneously developed without additional TACE procedures in one patient from the NBCA group. Permanent diaphragmatic weakness was less common in the NBCA than in the gelatin sponge group (12.6% and 25.2%, respectively; P = 0.017). The complete response rate did not significantly differ between the groups (NBCA group 16.2%; gelatin sponge group 25.9%; P = 0.065). CONCLUSION: Use of NBCA rather than gelatin sponge particles for TACE of the right IPA resulted in a lower incidence of permanent diaphragmatic weakness.

Anatomy of Left Inferior Phrenic Vein in Patients Without Portal Hypertension.

OBJECTIVE. The left inferior phrenic vein (LIPV) can be an origin of a gastrorenal shunt from gastric varices. The purpose of our study was to evaluate the angiographic anatomy of the LIPV, particularly anastomoses of the LIPV with the portal vein (PV). SUBJECTS AND METHODS. Of 240 patients with primary aldosteronism who underwent adrenal venous sampling from April 2011 to July 2019, 236 had normal liver and renal function and were included in this study. Of those patients, 214 had evaluable LIPV venography. The angiographic anatomy of the LIPV was classified as type 1 when the subdiaphragmatic transverse part of the LIPV could be visualized or as type 2 when it could not. Type 1 was subclassified into type 1a, which was defined as the transverse part of the LIPV connected with a single vein, or type 1b, which was defined as the transverse part of the LIPV connected with several veins via anastomoses. Type 2 LIPVs were subclassified into type 2a, in which the LIPV had an undeveloped vertical part; type 2b, in which the LIPV had backflow into systemic veins; or type 2c, in which the LIPV had a connection to the PV. The presence of an anastomosis with the PV was defined as the PV being visualizable on LIPV venography. RESULTS. Assessment of LIPV venography revealed type 1 in 71.5% (153/214) of patients, including type 1a (22.4%, 48/214) and type 1b (49.1%, 105/214). Type 2 LIPVs were observed in 28.5% (61/214) of patients, including types 2a (6.5%, 14/214), 2b (11.2%, 24/214), and 2c (10.7%, 23/214). An anastomosis of the LIPV with the PV was found in 28.0% (60/214) of patients, including 10.7% (23/214) with type 2c and 17.3% (37/214) with type 1 with a visible PV. The anastomoses of the LIPV with the PV were of various sizes. CONCLUSION. The angiographic anatomy of the LIPV varied and was commonly formed from several veins connected by anastomoses. An anastomosis between the LIPV and PV, which might be the origin of gastric varices, was found in 28.0% of patients.

A Novel Approach for Hepatic Arterial Reconstruction after Total Pancreatectomy with Common Hepatic Artery Resection Using Inferior Phrenic Artery.

BACKGROUND/AIMS: Because of the anatomical characteristics, pancreatic cancers (PC) can easily invade to visceral vessels such as celiac artery, superior mesenteric artery, common hepatic artery (CHA) and portal vein, which makes curative resection difficult. In this study, we report an R0 resection for locally advanced PC by total pancreatectomy, combined resection of CHA, and reconstruction of hepatic artery using autologous left inferior phrenic artery (IPA). METHODS: A 47-year-old woman with complaints of low back pain was referred to our department. Contrast-enhanced computed tomography revealed a hypo-attenuation tumor of the pancreatic body measuring 70 mm, which completely encased the CHA. When unresectable locally advanced PC was diagnosed, systematic chemotherapy was administrated. After downstaging, she underwent surgery with curative intent. The tumor completely infiltrated the peripheral part of the CHA and gastroduodenal artery. As the tumor also extended to the head of the pancreas, total pancreatectomy and combined resection of CHA were performed. Then the exposed left IPA and proper hepatic artery were anastomosed with a microvascular technique. RESULTS: R0 resection was performed for restoring hepatic arterial flow and the postoperative course was uneventful without any postoperative morbidity. CONCLUSION: Hepatic artery reconstruction using IPA is a simple and safe procedure in selected patients.

Variant morphology and arterial supply of diaphragmatic crura with probe patent foramen ovale.

Crura are the posterior pillars of the tendino-muscular partition between thoracic and abdominal cavity. This study highlights bilaterally an unfamiliar morphology of diaphragmatic crura with uncommon origin of inferior phrenic artery and accompanying atrial septal defect in a 63-years-old female cadaver with scoliosis. An attempt is made to portray the clinical implications of these variations. In addition authors have discussed the embryological and genetic basis of these variations. In the recent few decades, surgical correction of scoliosis involving intervention with the crura has gained pace. Knowledge about the normal as well as variant crural morphology is imperative for the surgeons to decide the correct approach during spinal corrective surgeries and for radiologist to prevent any diagnostic pitfall. Familiarity about the variant origin of inferior phrenic artery may prevent complications during treatment of pathological conditions related to inferior phrenic artery. Preoperative awareness about the coexisting atrial septal defect is vital for anesthesiologists promoting them to administer cardioprotective anesthetic drugs. To the best of our knowledge, description of such a combination of variations in anatomical literature is rare and scarcely reported. Awareness of these anatomical variations is relevant for operating surgeons, radiologists, anesthesiologists and anatomists.

Endotoxemia accelerates diaphragm dysfunction in ventilated rabbits.

BACKGROUND: Ventilators may induce diaphragm dysfunction, and most of the septic population who are admitted to the intensive care unit require mechanical ventilation. However, there is no evidence that sepsis accelerates the onset of ventilator-induced diaphragm dysfunction or affects the microcirculation. Our study investigated whether lipopolysaccharide (LPS)-induced endotoxemia accelerated diaphragm dysfunction in ventilated rabbits by evaluating microcirculation, lipid accumulation, and diaphragm contractility. METHODS: After anesthesia and tracheostomy, 25 invasively monitored and mechanically ventilated New Zealand white rabbits were randomized to control (n = 5), controlled mechanical ventilation (CMV) (n = 5), pressure support ventilation (PSV; n = 5), CMV or PSV with LPS-induced endotoxemia (CMV-LPS and PSV-LPS, respectively; n = 5 for each). Rabbits were anesthetized and ventilated for 24 h, except the control rabbits (30 min). Diaphragmatic contractility was evaluated using neuromechanical and neuroventilatory efficiency. We evaluated the following at the end of the protocol: (1) diaphragm microcirculation; (2) lipid accumulation; and (3) diaphragm muscular fibers structure. RESULTS: Diaphragm contractility, microcirculation, lipid accumulation, and fiber structures were severely compromised in endotoxemic animals after 24 h compared to nonendotoxemic rabbits. Moreover, a slight but significant increase in lipid accumulation was observed in CMV and PSV groups compared with controls (P < 0.05). CONCLUSIONS: Endotoxemia accelerates the diaphragm dysfunction process in ventilated rabbits, affects the microcirculation, and results in diaphragmatic lipid accumulation and contractility impairment.

[CLINICAL SIGNIFICANCE OF ANATOMICAL VARIABILITY OF THE LEFT INFERIOR PHRENIC VEIN].

The diaphragm was taken from the corpses of 80 humans of both sexes of adult age and was studied using the complex of preparation, injection, morphometric and of variational-statistical methods. A significant anatomical variation of the left inferior phrenic veins was found, that was characterized by different variants of their confluence, and variation of their diameters. Five variants of the confluence of the left inferior phrenic veins were defined. It was shown that the variant of confluence of the left inferior phrenic veins into a single trunk fusing with the inferior vena cava was suitable for catheterization. Suitable for catheterization left inferior phrenic veins may be divided into freely catheterizable (diameter of 5 mm and more).and conditionally catheterizable (diameter less Than 5 mm). When performing cardiac resynchronization therapy, the vein can be used as an alternative way (along with the coronary sinus of the heart) for transvenous delivery system of stimulation electrode. Variants of confluence of the left inferior phrenic vein in hepatic and adrenal veins were not suitable for catheterization.

[SURGICAL ANATOMY OF THE TRIBUTARIES OF INFERIOR VENA CAVA].

The results of the anatomical study of the inferior vena cava (IVC) and its tributaries on 27 fresh cadavers were analysed. It was established that in past hepatic part of IVC fall from 7 to 23 veins. The diameter of the main hepatic veins on average 12.3 mm, and back ­ 4.8 mm. In 63% of cases between the main and back hepatic veins have a free box of length 10 ­ 18 mm. Lumbar vein 2 ­ 8 pairs of branches in 92.6% of cases merge and flow into the IVC by one trunk, often closer to her left hemi circle. The diameter of the joint lumbar vein average 5.2 mm. Upper joint lumbar vein falls into the IVC at a distance of 13 ­ 23 mm from the confluence of the right renal vein. Back hepatic and joint lumbar vein may be a source of intraoperative bleeding, that is difficult to control. Identified anatomical features tributaries of IVC below the diaphragm should be borne in mind when removing blood clots from the IVC.

Diaphragmatic function is preserved during severe hemorrhagic shock in the rat.

BACKGROUND: Acute diaphragmatic dysfunction has been reported in septic and cardiogenic shock, but few data are available concerning the effect of hemorrhagic shock on diaphragmatic function. The authors examined the impact of a hemorrhagic shock on the diaphragm. METHODS: Four parallel groups of adult rats were submitted to hemorrhagic shock induced by controlled exsanguination targeting a mean arterial blood pressure of 30 mmHg for 1 h, followed by a 1-h fluid resuscitation with either saline or shed blood targeting a mean arterial blood pressure of 80 mmHg. Diaphragm and soleus strip contractility was measured in vitro. Blood flow in the muscle microcirculation was measured in vivo using a Laser Doppler technique. Muscle proinflammatory cytokine concentrations were also measured. RESULTS: Hemorrhagic shock was characterized by a decrease in mean arterial blood pressure to 34 ± 5 mmHg (-77 ± 4%; P< 0.05) and high plasma lactate levels (7.6 ± 0.9 mM; P < 0.05). Although tetanic tension of the diaphragm was not altered, hemorrhagic shock induced dramatic impairment of tetanic tension of the soleus (-40 ± 19%; P < 0.01), whereas proinflammatory cytokine levels were low and not different between the two muscles. Resuscitation with either blood or saline did not further modify either diaphragm or soleus performance and proinflammatory cytokine levels. The shock-induced decrease in blood flow was much more pronounced in the soleus than in the diaphragm (-75 ± 13% vs. -17 ± 10%; P = 0.02), and a significant interaction was observed between shock and muscle (P < 0.001). CONCLUSION: Diaphragm performance is preserved during hemorrhagic shock, whereas soleus performance is impaired, with no further impact of either blood or saline fluid resuscitation.

Diaphragm disease of the small bowel: a retrospective review of CT findings.

OBJECTIVE: The purpose of this article is to report the CT findings of pathologically proven diaphragm disease in the small bowel. MATERIALS AND METHODS: A retrospective review identified 12 patients with pathologically proven small-bowel diaphragm disease who underwent CT within 6 months of surgical resection. Two radiologists, who were unblinded to pathologic and clinical findings, evaluated CT examinations for imaging findings of disease extent, appearance, and location. Clinical history and postoperative follow-up were also performed. RESULTS: The most common presenting symptoms were abdominal pain (7/12 [58%]) and anemia (5/12 [42%]). Long-term use of nonsteroidal antiinflammatory drugs was documented in 58% (7/12) of patients. The most common location of small-bowel diaphragms was the ileum (8/12 [67%]). The CT findings were abnormal in 92% (11/12) of patients. The most common CT findings were small-bowel strictures (11/12 [92%]) and focal (median length, 1 cm) bowel wall thickening (8/12 [67%]). Other less common CT findings included mucosal hyperenhancement (6/12 [50%]), small-bowel dilatation (5/12 [42%]), and video capsule retention (6/9 [67%]). Postoperative follow-up in 11 patients found recurrent symptoms in four patients. CONCLUSION: Small-bowel diaphragm disease should be considered in patients with a history of long-term use of nonsteroidal antiinflammatory drugs, chronic abdominal pain, and anemia who present with CT findings of short, symmetric ileal strictures and focal bowel wall thickening.

A morphological study of the inferior phrenic arteries on multidetector computed tomography and angiography.

INTRODUCTION: The inferior phrenic artery is a paired artery with a variable origin and course, primarily supplying the diaphragm, but also the suprarenal glands, inferior vena cava, stomach, and oesophagus. The aim of this study is to investigate the origin and course of the inferior phrenic arteries on multidetector computed tomography and angiography. MATERIALS AND METHODS: The anatomy of the inferior phrenic artery was analysed on 2449 multidetector computed tomography scans. Three-dimensional reconstructions were made of the main variations. Additionally, the course and branching pattern of the inferior phrenic artery were descriptively analysed in a cohort of 28 angiograms. RESULTS: In 565 (23.1%) cases the inferior phrenic arteries arose as a common trunk and in 1884 (76.9%) cases as individual vessels. The most common origins of a common trunk were the coeliac trunk (n=303; 53.6%) and abdominal aorta (n=255; 45.1%). The most common origins of the right inferior phrenic artery were the coeliac trunk (n=965; 51.2%), abdominal aorta (n=562; 29.8%) and renal arteries (n=214; 11.4%). The most common origins of the left inferior phrenic artery were the coeliac trunk (n=1293; 68.6%) and abdominal aorta (n=403; 21.4%). CONCLUSION: The inferior phrenic artery has a very variable anatomy. The most common origins of the inferior phrenic artery are the coeliac trunk and its branches, the abdominal aorta, and the renal arteries.

Neurovascular proximity in the diaphragm muscle of adult mice.

OBJECTIVE: Regional blood flow to the diaphragm muscle varies with the workload of inspiration. To provide anatomical insight into coupling between muscle fiber recruitment and oxygen supply, we tested whether arterioles are physically associated with motor nerve branches of the diaphragm. METHODS: Following vascular casting, intact diaphragm muscles of C57BL/6 and CD-1 mice were stained for motor innervation. Arteriolar networks and nerve networks were mapped (~2 µm resolution) to evaluate their physical proximity. RESULTS: Neurovascular proximity was similar between muscle regions and mouse strains. Of total mapped nerve lengths (C57BL/6, 70 ± 15 mm; CD-1, 87 ± 13 mm), 80 ± 14% and 67 ± 10% were ≤250 µm from the nearest arteriole and associated predominantly with arterioles ≤45 µm in diameter. Distances to the nearest arteriole encompassing 50% of total nerve length (D(50)) were consistently within 200 µm. With nerve networks repositioned randomly within muscle borders, D(50) values nearly doubled (p < 0.05). Reference lines within anatomical boundaries reduced proximity to arterioles (p < 0.05) as they deviated from the original location of motor nerves. CONCLUSION: Across two strains of mice, motor nerves and arterioles of the diaphragm muscle are more closely associated than can be explained by chance. We hypothesize that neurovascular proximity facilitates local perfusion upon muscle fiber recruitment.

Mechanical ventilation reduces rat diaphragm blood flow and impairs oxygen delivery and uptake.

OBJECTIVES: Although mechanical ventilation is a life-saving intervention in patients suffering from respiratory failure, prolonged mechanical ventilation is often associated with numerous complications including problematic weaning. In contracting skeletal muscle, inadequate oxygen supply can limit oxidative phosphorylation resulting in muscular fatigue. However, whether prolonged mechanical ventilation results in decreased diaphragmatic blood flow and induces an oxygen supply-demand imbalance in the diaphragm remains unknown. DESIGN: We tested the hypothesis that prolonged controlled mechanical ventilation results in a time-dependent reduction in rat diaphragmatic blood flow and microvascular PO2 and that prolonged mechanical ventilation would diminish the diaphragm's ability to increase blood flow in response to muscular contractions. MEASUREMENTS AND MAIN RESULTS: Compared to 30 mins of mechanical ventilation, 6 hrs of mechanical ventilation resulted in a 75% reduction in diaphragm blood flow (via radiolabeled microspheres), which did not occur in the intercostal muscle or high-oxidative hindlimb muscle (e.g., soleus). There was also a time-dependent decline in diaphragm microvascular PO2 (via phosphorescence quenching). Further, contrary to 30 mins of mechanical ventilation, 6 hrs of mechanical ventilation significantly compromised the diaphragm's ability to increase blood flow during electrically-induced contractions, which resulted in a ~80% reduction in diaphragm oxygen uptake. In contrast, 6 hrs of spontaneous breathing in anesthetized animals did not alter diaphragm blood flow or the ability to augment flow during electrically-induced contractions. CONCLUSIONS: These new and important findings reveal that prolonged mechanical ventilation results in a time-dependent decrease in the ability of the diaphragm to augment blood flow to match oxygen demand in response to contractile activity and could be a key contributing factor to difficult weaning. Although additional experiments are required to confirm, it is tempting to speculate that this ventilator-induced decline in diaphragmatic oxygenation could promote a hypoxia-induced generation of reactive oxygen species in diaphragm muscle fibers and contribute to ventilator-induced diaphragmatic atrophy and contractile dysfunction.

Pseudoaneurysm of the inferior phrenic artery presenting as an upper gastrointestinal bleed by directly rupturing into the stomach in a patient with chronic pancreatitis.

Pseudoaneurysms occurring in patients with chronic pancreatitis are associated with significant morbidity and mortality. These pseudoaneurysms occur more commonly in the splenic, pancreaticoduodenal, and gastroduodenal arteries. Upper gastrointestinal bleeding (UGIB) due to pseudoaneurysms in patients with pancreatitis with pseudocyst usually presents as hemosuccus pancreaticus. However, pseudoaneurysm directly perforating the gastrointestinal tract and presenting as UGIB is a rare complication. We report here the first case of UGIB from the inferior left phrenic artery pseudoaneurysm rupturing directly into the stomach of a patient with chronic pancreatitis.

The right inferior phrenic artery: path of its ascending branch at the vena caval foramen.

The ascending branch of the right inferior phrenic artery is generally understood to pass to the lateral side of the vena caval foramen, on the inferior surface of the diaphragm. A study of 16 cadavers shows that the artery may pass through the vena caval foramen to run on the superior surface of the diaphragm, before returning to the inferior surface by passing through the muscle of the diaphragm.

Rare case of the trunk of the inferior phrenic arteries originating from a common stem with a superior additional left renal artery from the abdominal aorta.

We describe in this article a rare case of a 39-year-old male with an inferior phrenic arteries trunk (IPAaT) originating from a common stem with a superior additional left renal artery (SAdLRA) from the abdominal aorta as revealed by routine multidetector computed tomography angiography. The IPAaT with an endoluminal diameter at the origin of 2.8 mm had an upward path with a total length of 18.4 mm, forking to the right inferior phrenic artery and left inferior phrenic artery. These two arteries had an endoluminal diameter at the origin of 1.7 mm and 2.0 mm, respectively. The presence of the common stem of the IPAaT with a SAdLRA and the length of the IPAaT complicate selective chemoembolization of the liver parenchyma.