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Biomedical subjects

M V Marx

Publications and source records attributed to M V Marx.

At least 37 records · Page 2Linked to original sources
PubMed1992

Acute traumatic aortic rupture: intravascular US findings.

Traumatic aortic rupture is a lethal injury that requires immediate diagnosis and surgical repair. The authors report a case of acute aortic rupture in which aortography demonstrated a subtle intimal discontinuity at the cephalic margin of the aortic spindle. Intravascular ultrasound (US) imaging of the aorta demonstrated a mural flap and a small, contained hematoma. Intravascular US may have a role in enabling confirmation or clarification of subtle aortic abnormalities.

Adult↗
PubMed1992

Superelastic guide-wire snare for removal of foreign bodies from the urinary tract.

A superelastic guide wire was used (after failure of other methods) as a loop snare to retrieve a foreign body from the ureter in three patients. In vitro comparison of the expansion capability of the superelastic guide wire and that of the standard retrieval wire showed that the superelastic wire forms larger loops within an elastic space. Also, because of less frictional resistance and its ability to be formed into stiffer loops, the superelastic wire resists kinking and is easier to manipulate than the standard wire.

Aged↗
PubMed1992

Massive upper gastrointestinal hemorrhage with normal findings on arteriography: value of prophylactic embolization of the left gastric artery.

During a 5-year period, 13 patients who presented with massive upper gastrointestinal hemorrhage had normal findings on arteriography. Seven had prophylactic embolization of the left gastric artery, and six had conservative therapy. Normal angiographic findings were associated with clinical cessation of bleeding in 12 of 13 patients. Lesions not treated by embolization or other invasive therapy had a high rate of massive recurrent hemorrhage (four of six). Of lesions subsequently found to be supplied by the left gastric artery, two of four cases not treated by embolization or surgery had clinically significant recurrent hemorrhage, whereas none of six cases treated by embolization had recurrent hemorrhage. Prophylactic embolization of the left gastric artery appears warranted when (1) there is definite prior identification of a lesion in the left gastric artery territory or (2) there is no prior localization of a lesion but the patient is at risk for multiorgan failure if bleeding recurs.

Adult↗
PubMed1991

Evaluation of the inferior vena cava with intravascular US after Greenfield filter placement.

An animal model was used to evaluate the utility of intravascular ultrasound (US) imaging of the inferior vena cava (IVC) following Greenfield filter placement. Ten Greenfield filters were placed in the IVCs of five sheep and three dogs. Experimentally induced thrombi were injected into four filters at the time of placement. Intravascular US and cavography were performed 4 weeks after filter implant. The imaging studies were evaluated for demonstration of filter position, orientation, and leg distribution, as well as prediction of caval wall penetration by filter hooks. Experimentally induced and spontaneous intrafilter thrombi were also imaged. Findings were compared with those of postmortem examination. Exact filter position and orientation were most simply and accurately demonstrated on radiographs. Filter leg distribution and extent of intrafilter thrombus were best evaluated on intravascular US images. The prevalence of caval wall penetration was underestimated with both studies. The results of this animal study suggest that the information about the IVC provided at cavography and intravascular US following Greenfield filter placement may be complementary.

Animals↗
PubMed1991

Intravascular ultrasound imaging of vascular responsiveness in isolated perfused canine arteries.

We investigated the feasibility of using intravascular ultrasound imaging to analyze vascular physiology in various arterial beds. Canine superficial femoral, external iliac, and common carotid arteries were harvested and suspended and perfused in a bath of oxygenated, heated, physiologic salt solution. A 6-Fr, 20-MHz ultrasound imaging catheter was inserted into the lumen of the arteries and serial images were acquired after bolus injections of either serotonin or normal saline into the extravascular bathing medium. Serotonin resulted in a significant time- and dose-dependent decrease in cross-sectional area in muscular femoral arteries (P less than .001): -5.2% with 10(-8) M serotonin, -15% with 10(-7) M, and -28% with 10(-6) M. Histologically transitional iliac arteries demonstrated less marked changes, while elastic carotid arteries demonstrated no significant changes. Our results indicate that intravascular ultrasound may be used to quantify and differentiate responses to vasoconstrictive agents in different vascular beds.

Animals↗
PubMed1991

Evaluation of a new percutaneous stainless steel Greenfield filter by intravascular ultrasonography.

The standard stainless steel Greenfield filter was modified by extending the limbs at the apex to permit loading into a 12F carrier for percutaneous insertion. This model was tested for fixation and resolution of experimental embolism in dogs (six filters in four dogs) and sheep (eight suprarenal filters in eight sheep). Serial radiographs and venacavography at 2 and 4 weeks allowed measurement of migration and suspected caval penetration, confirmed by direct examination at autopsy. Caval penetration was graded according to visibility of point (0), hook (1+), or limb (2+) for each limb of the filter. Oxidized cellulose-induced thrombi were injected and trapped in two dogs and four sheep without proximal filter displacement or thrombus propagation. Thrombi showed incomplete resolution during 4 weeks' observation by interval venacavography and subsequent autopsy but no tendency for proximal propagation. Distal migration occurred in four of six filters in dogs, and caval wall penetration was seen (score 1.8/filter). Less migration was seen in sheep (2/8), but there was evidence of hook penetration in four animals (score 0.88/filter). Intravascular ultrasonography, 20 MHz, with a 6.5 F catheter assembly successfully visualized all 10 filters in which it was attempted and showed thrombi attached to the filter or caval wall, all of which were confirmed at explant. No thrombi were missed; however, intravascular ultrasonography was limited in assessment of caval wall penetration by lack of position control and reverberation artifact. Although it performs well as a filter, the elasticity of the percutaneous stainless steel greenfield filter allows distal migration and caval penetration comparable to the titanium Greenfield filter and will require further modification of hook design to improve performance.

Animals↗
PubMed1990

Massive arterial hemorrhage from the stomach and lower esophagus: impact of embolotherapy on survival.

The authors retrospectively reviewed the clinical courses in 36 patients referred for angiographic evaluation of massive arterial hemorrhage from the stomach, gastroesophageal junction, and lower esophagus. Twenty-four patients underwent embolotherapy, and 12 were treated with nontranscatheter therapy such as surgery, Sengstaken-Blakemore tube placement, endoscopic submucosal injection of epinephrine, or supportive medical therapy. Bleeding was controlled completely in 15 (62%) and partially in three (13%) of the patients who underwent embolotherapy. In nine of the patients treated with nontranscatheter therapy (75%), bleeding control was complete. Sixteen patients died, including seven of 28 in whom bleeding was controlled. There was no significant difference in the mortality rates of patients treated with nontranscatheter therapy (46% and 42%, respectively). Survival correlated with the clinical condition at the time of intervention. All patients with multiorgan failure died, while 87% of the other patients, even those with serious cardiovascular compromise, survived. The results imply that massive gastric hemorrhage should be treated aggressively, before it results in multiorgan failure.

Acute Disease↗
PubMed1990

Fluoroscopically guided percutaneous gastrostomy and gastroenterostomy: analysis of 158 consecutive cases.

We reviewed our experience with 158 consecutive patients who underwent either percutaneous gastrostomy or percutaneous gastroenterostomy during a 2-year period. The catheters used included Foley catheters (36), Cope-type gastric catheters (86), or Carey-Alzate-Coons gastrojejunostomy catheters (36). Gastrojejunostomy tubes were placed in patients with gastroesophageal reflux or aspiration, gastric atony, or partial gastric obstruction. Ninety percent of the tubes were placed for feeding purposes. The technical success rate was 100%. Thirty-day follow-up was obtained in 89%. Thirty-day mortality was 26%, reflecting the substantial number of debilitated patients. No deaths were directly related to tube placement. Major morbidity was 6% and included hemorrhage, peritonitis, tube migration, and sepsis. Minor morbidity was 12%. There was no difference in 30-day mortality or feeding tolerance between the tube types (p less than .05). Patients with Foley catheters had more complications necessitating surgical intervention and an increased incidence of tube changes required within 30 days. These were the only statistically significant differences between the tubes (p less than .05). Our results show that percutaneous gastrostomy is a safe and effective means of gastroenteric feeding or decompression. Because of the fewer complications and ease of insertion, the Cope type of gastrostomy tube has become our preferred catheter for percutaneous feeding or decompression.

Aged↗
PubMed1989

Role of percutaneous intracorporeal electrohydraulic lithotripsy in the treatment of biliary tract calculi. Work in progress.

Although surgery is the treatment of choice for symptomatic gallstones, most bile duct calculi can be successfully treated with the use of routine percutaneous or endoscopic methods. Failure of these methods is most often associated with stones larger than 1.5 cm. The authors used percutaneous intracorporeal electrohydraulic lithotripsy (EHL) to treat 11 patients with calculi in the bile ducts (n = 10) or gallbladder (n = 1) in whom the use of other percutaneous or endoscopic methods failed. The stones in all 11 patients were successfully fragmented and removed. There were no complications. Intracorporeal EHL is an effective alternative therapy for the treatment of biliary tract calculi when standard methods fail.

Aged↗
PubMed1989

Percutaneous cholecystolithotomy: preliminary experience and technical considerations.

Surgical cholecystectomy is associated with a high morbidity and mortality in elderly patients with acute calculous cholecystitis and underlying cardiac or pulmonary disease. Currently there are few alternatives for treating these patients. The authors have used percutaneous cholecystolithotomy in 11 such high-risk patients for definitive treatment of gallbladder calculi. In all 11 patients all stones were successfully removed from the gallbladder and cystic duct. The entire procedure--from initial tube placement to final tube removal--lasted 17-40 days (mean, 21 days). There were two complications: one minor--local wound infection--and one major--bile peritonitis with eventual death. Percutaneous cholecystolithotomy is an effective alternative therapy for acute calculous cholecystitis in elderly, debilitated patients.

Aged↗
PubMed1989

Color Doppler sonography of hemodialysis vascular access: comparison with angiography.

This study was performed to define the color Doppler sonographic appearance of normal and abnormal hemodialysis vascular access and to compare color Doppler sonography with angiography. Twenty-eight patients (nine with Brescia-Cimino fistulas and 19 with synthetic grafts) were imaged with digital subtraction angiography and color Doppler sonography. The examinations were interpreted independently and then interpreted together to determine the accuracy of the two methods. With angiography as the gold standard, color Doppler sonography correctly identified 20 of 23 stenosed vessels, three of four occluded vessels, four of four thrombosed vessels, and 18 of 19 pseudoaneurysms. Overall, color Doppler sonography correctly identified all lesions that were seen angiographically in 16 of 19 patients with synthetic grafts and in four of nine patients with Brescia-Cimino fistulas. Five asymptomatic arterial steals were detected sonographically. One of these was identified with angiography. Color Doppler sonography is an adequate means of imaging suspected complications of hemodialysis vascular access, and it should be used in selected patients. However, digital subtraction angiography is more sensitive and should be the initial imaging technique for most of these patients.

Adult↗
PubMed1988

Cholescintigraphy in the critically ill.

Critical review of cholescintigraphy in critically ill patients suggests the examination will not conclusively prove or disprove the diagnosis of acute cholecystitis. Of 17 scans performed in critically ill patients with clinical evidence of acute cholecystitis, 7 were true-negative, 1 was false-negative, 6 were false-positive, and 3 were nondiagnostic. Cholestasis and hepatocyte dysfunction, common in the critically ill, result in abnormal clearance of hepatobiliary radionuclide imaging agents, decreasing the usefulness of cholescintigraphy in this patient population. Diagnosing acute cholecystitis in a critically ill patient remains difficult.

Acute Disease↗
PubMed1988

Chronic intestinal obstruction: value of percutaneous gastrostomy tube placement.

Percutaneous gastrostomy tubes were placed in six patients for treatment of nausea and vomiting associated with chronic intestinal obstruction. There were no complications related to the tubes, and in all patient, symptoms were relieved. For the patient, the advantages of gastrostomy over nasogastric drainage include improved comfort, increased mobility, and a decreased risk of pulmonary aspiration. Percutaneous gastrostomy is a safe procedure and provides excellent palliation for intractable nausea and vomiting in patients with chronic intestinal obstruction.

Adult↗