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W Ganz

Publications and source records attributed to W Ganz.

At least 19 recordsLinked to original sources
PubMed2001

Defining radiographic criteria for flexion-extension studies of the cervical spine.

STUDY OBJECTIVE: We sought to describe and measure 3 radiographic variables in normal male volunteers and determine whether these variables could be useful in establishing more objective radiographic criteria for evaluation of flexion-extension studies of the cervical spine. In addition, we hypothesized that patients with a normal cervical spine should not have greater than 2 mm of subluxation present with flexion or extension. METHODS: A prospective, observational study of normal male volunteers between the ages of 18 and 40 years was performed. We obtained radiographs of all participants in neutral, flexion, and extension positions and measured the amount of subluxation and interspinous distance, as well as the degree of vertebral angulation between C3 and C7. RESULTS: One hundred male volunteers were included in the study. Subluxation during flexion (compared with neutral) was greater than 2 mm in none of the participants at each level from C3 to C7 (95% confidence interval [CI] 0 to 3.6); subluxation in extension was greater than 2 mm in one participant at one level from C3 to C4 (95% CI 0 to 5.5) and none of the participants at each of the remaining 3 levels from C4 to C7 (95% CI 0 to 3.6). Comparing flexion with the neutral position, the mean vertebral angulation and SD were 24.2 degrees and 13.3 degrees, and the 95% certainty interval (CEI) was -1.9 to 50.2. Comparing extension with the neutral position, the mean vertebral angulation was 14.1 degrees, with an SD of 13.3 degrees, and the 95% CEI was -4.6 to 32.8. The mean change in interspinous distance between the neutral position and flexion varied from 1.2 to 4.6 mm (SD 1.7 to 2.4 mm), depending on the level of cervical spine studied. When comparing the neutral position and extension, the mean change in interspinous distance varied from 1.2 to 2.2 mm (SD 1.7 to 1.9). CONCLUSION: Currently, there are no clinically validated criteria for evaluating flexion-extension studies of the cervical spine. Our study suggests that subluxation greater than 2 mm in men 18 to 40 years of age may be a useful variable for further study as an indicator of ligamentous injury. Interspinous distance and vertebral angulation appear less likely to have useful clinical application.

Adolescent↗
PubMed1996

Surveillance imaging in children with primitive neuroectodermal tumors.

Controversy surrounds the benefits of routine surveillance magnetic resonance or computed tomographic imaging for monitoring children after resection of primitive neuroectodermal tumors. A recent study suggested that serial imaging studies detect only a small minority of tumor recurrences in patients with symptoms. The authors concluded that even in patients with recurrence documented by imaging, no patient with a recurrence survived long (average, 5 mo) and that surveillance scanning is of little clinical value in children with primitive neuroectodermal tumors. We reviewed our experience with 25 patients (28% of our total series) who presented to the Children's Hospital Los Angeles, Los Angeles, CA, from 1985 to 1993 with recurrent tumors after surgery and adjuvant therapy. Recurrent tumors were detected on routine imaging in 19 asymptomatic patients (76%) and in 6 symptomatic patients (24%). Recurrences were documented 15 months (mean) after the initial diagnosis in asymptomatic children and 5 months (mean) after the initial diagnosis in children with symptoms of recurrent tumor (P < or = 0.01). Asymptomatic patients with recurrence documented on serial imaging had prolonged survival when compared with those who were symptomatic (P < or = 0.05). The surviving patients with recurrence remained alive for more than 24 months after documentation of recurrence. Early detection of local tumor recurrence by surveillance scanning may provide a critical therapeutic window for successful treatment with aggressive or novel therapies.

Adolescent↗
PubMed1996

Efficient parathyroidectomy guided by SPECT-MIBI and hormonal measurements.

UNLABELLED: Parathyroidectomy is a difficult and lengthy operation which is noncurative in 6% to 10% of cases. To improve the efficiency of this operation, a new dual diagnostic approach was prospectively applied. METHODS: Preoperative tomographic 99mTc-sestamibi (MIBI) scintography and intraoperative measurements of circulating parathyroid hormone (PTH) levels by a quick assay (QPTH) were used. Scintigraphy comprised immediate and delayed planar and SPECT of the neck and chest, following 20 mCi MIBI. The presence and location of persistent foci of abnormal activity found within the neck mediastinum on volume-rendered reprojection (RPJ) of the SPECT data were reported. The surgion, guided by the three-dimensional MIBI-SPECT/RPJ images, identified and excised the single or most prominent scintigraphic focus and applied the QPTH. If PTH levels fell from baseline by at least 50%, the operation was concluded. RESULTS: The operative time of primary parathyroidectomy was reduced from an average of 90 min (before the introduction of scintigraphy and intraoperative PTH measurements) to 57 min. All but two patients became normocalcemic. In 58 consecutive patients with hyperparathyroidism, MIBI-SPECT/RPJ correctly and precisely identified 51 of 53 (96%) primary parathyroid adenomas, 14 to 15 secondary hyperplasias and 2 of 3 hyperplastic glands in MEN (sensitivity 94%, specificity 92%). QPTH verified the excision of the primary parathyroid adenomas and predicted normocalcemia in 50 of 52 patients. In 6 patients with misleading scintigraphy, QPTH was especially useful and guided the surgeon to continue the operation until the abnormal parathyroid tissue was found and excised. CONCLUSION: MIBI-SPEC/RPJ and QPTH sequentially applied improved the efficiency of parathyroidectomy.

Adenoma↗
PubMed1995

Absence of lethal reperfusion injury after 3 hours of reperfusion. A study in a single-canine-heart model of ischemia-reperfusion.

BACKGROUND: Whether reperfusion can cause necrosis of previously viable myocytes (lethal reperfusion injury) remains controversial. Numerous studies examined the ability of various agents to prevent or limit reperfusion injury, but the results were contradictory. In a single-canine-heart model of ischemia-reperfusion, we previously demonstrated that 5 minutes of reperfusion does not increase the transmural extent of necrosis. Since the 5-minute period of reperfusion is considered by some to be too short for the full manifestation of reperfusion injury, we reexamined the issue of lethal reperfusion injury using a modification of the single-heart model of ischemia-reperfusion that allowed extending the reperfusion period to 3 hours. METHODS AND RESULTS: In anesthetized, open-chest dogs, the distal half of the left anterior descending coronary artery (LAD) segment between the last diagonal branch and the apex was perfused via a shunt from the left carotid artery. The shunt was closed for periods of 90 to 180 minutes, depending on the ECG severity of ischemia, and reperfused for 3 hours. While the distal region was perfused from the carotid artery, the LAD was occluded proximal to the last diagonal branch for the same period of time as the distal region had been earlier. The time of occlusion was chosen such that the end of the occlusion period coincided with the end of the experiment. Thus, both regions of the LAD territory were subjected to identical periods of ischemia, but only the distal region was reperfused. At the end of the experiment, the boundary between the proximal (nonreperfused) and distal (reperfused) area was delineated by blue dye, and the heart was arrested, cut into slices 1 cm thick parallel to the LAD, and placed in triphenyltetrazolium chloride. The epicardial edges of necrosis in the reperfused and the nonreperfused regions were examined for any shift that might suggest a difference in the transmurality of necrosis. The areas of necrotic and viable myocardium were measured by planimetry within 1 cm on either side of the boundary. In all 14 dogs, the epicardial edges of necrosis ran as a single line across the boundary, and no shift was present. There was also no difference in the transmurality of necrosis between the reperfused and nonreperfused regions (64.9 +/- 20.7% versus 66.1 +/- 17.0% of left ventricular wall thickness, respectively, P = .32 by paired t test). CONCLUSIONS: In a single-canine-heart model of ischemia-reperfusion, there was no evidence of lethal reperfusion injury after 3 hours of reperfusion.

Animals↗
PubMed1995

Cardiovascular magnetic resonance imaging goes beyond anatomy.

Magnetic resonance imaging (MRI) provides noninvasive functional information as well as a three-dimensional anatomic display of the cardiovascular system. MRI of protons, phosphorus, or sodium nuclei is currently being investigated to characterize cardiovascular pathology, and the potential benefits of paramagnetic contrast agents are becoming apparent. Finally, techniques to quantitate blood flow, vascular pressures, chamber volumes, ventricular ejection fractions, and cardiac output are being developed.

Contrast Media↗
PubMed1993

Angiographic validation of bedside markers of reperfusion.

OBJECTIVES: We sought to validate with coronary angiography several primary and ancillary markers of reperfusion. BACKGROUND: The availability of bedside markers of reperfusion is of major importance in the thrombolytic therapy of acute myocardial infarction. However, the reliability of current markers is still controversial. METHODS: Changes in chest pain, ST segment elevation and heart rate and rhythm were assessed every 5 to 10 min for up to 3 h after initiation of recombinant tissue-type plasminogen activator therapy in 82 patients with acute myocardial infarction. Coronary angiography was performed within 24 h. RESULTS: At angiography, 69 of the 82 patients had a patent infarct-related artery with Thrombolysis in Myocardial Infarction trial (TIMI) grade 3 flow and a rapid and progressive decrease in chest pain and ST elevation. The pain resolved in 24 +/- 23 min (range 3 to 50). The ST elevation decreased by > or = 50% within 16 +/- 14 min (range 5 to 41). Accelerated idioventricular rhythm developed in 49% of patients and sinus bradycardia in 23%; conduction abnormalities and atrial fibrillation resolved. All markers appeared in close temporal proximity to the onset of an abrupt increase in plasma creatine kinase (CK) and CK-MB isoenzyme activity, a previously validated marker of the time of reperfusion. Before its final resolution, ST elevation transiently decreased and increased in 58% of patients. Comparison of one pretreatment and one posttreatment electrocardiogram significantly reduced the reliability of ST segment change as a marker of reperfusion. In 13 of 82 patients, the infarct-related artery demonstrated TIMI grade < or = 2 flow; in 9, pain and ST elevation did not lessen and CK and CK-MB activity showed no abrupt increase. The remaining four patients initially demonstrated a decrease in pain and ST elevation; however, within 3 h and before angiography, the recurrence of pain and ST elevation suggested reocclusion. CONCLUSIONS: A rapid and progressive decrease in pain and ST elevation is a reliable marker of reperfusion with TIMI grade 3 flow. Because ST elevation and pain often fluctuate before undergoing final resolution with reperfusion, frequent or continuous monitoring of ST elevation is essential for reliable recognition of the fact and time of reperfusion. Accelerated idioventricular rhythm and episodes of sudden sinus bradycardia, although specific to reperfusion, do not occur in all patients with reperfusion.

Aged↗
PubMed1991

Clinical utility of a position-monitoring catheter in the pulmonary artery.

Unsuspected distal migration of the tip of the pulmonary artery catheter may cause life-threatening complications. We prospectively evaluated the clinical utility of the PA Watch Catheter in 25 patients after cardiac surgery by hourly measurements of pulmonary artery (distal lumen), right ventricular (middle lumen), and central venous (proximal lumen) pressures. The catheter was considered to be in the proper position when the middle lumen port, located 10 cm from the tip, transmitted a right ventricular pressure waveform. Satisfactory initial catheter placement was obtained in 24 of 25 patients. During the 28.4 +/- 1.8 h of postoperative monitoring, clinically unsuspected distal catheter migration, indicated by the presence of a pulmonary artery pressure waveform in the middle lumen port, occurred in 12 of the 25 patients (48%). In these patients, 20 episodes occurred and required catheter withdrawal distances of 1.8 +/- 0.3 cm (range 1-6 cm). The PA Watch Catheter proved to be a useful indicator of unsuspected distal catheter migration in the postoperative period. The PA Watch Catheter allows assessment of catheter tip placement in the proximal pulmonary artery and may decrease catheter-induced complications.

Adult↗
PubMed1991

New method for monitoring pulmonary artery catheter location.

OBJECTIVE: To test the ability of a modified pulmonary artery (PA) monitoring catheter to detect distal catheter migration. DESIGN: Prospective nonrandomized trial. PATIENTS: Surgical ICU patients requiring invasive hemodynamic monitoring. INTERVENTIONS: Eight patients received PA catheters modified to include a right ventricular (RV) pressure monitoring port located 7 cm from the tip. Fifteen patients received catheters with an RV port located 10 cm from the tip. Guided by the RV port pressure waveform, catheters were initially positioned so that the RV port was located just proximal to the pulmonic valve. MEASUREMENTS AND MAIN RESULTS: Pulmonary capillary occlusion pressure (PAOP) could not be obtained in six of the eight patients receiving the 7-cm RV port catheter unless the RV port was advanced into the PA. PAOP was consistently obtained in all 15 patients receiving the 10-cm RV port catheter, with the RV port positioned in the RV. Chest radiographs confirmed a central PA catheter position. In this group, distal migration of the catheter occurred 14 times in eight patients, as detected by appearance of a PA pressure waveform at the RV port. Distal migration was corrected by withdrawal of the catheter until an RV waveform reappeared at the RV port. CONCLUSIONS: We conclude that distal catheter migration occurs frequently with PA monitoring catheters, but can be detected at the bedside with a catheter modified to include an RV port 10 cm from the tip. This new catheter may add a margin of safety to PA monitoring and lower its overall cost by eliminating the need for chest radiographs ordered solely to confirm catheter tip location.

Aged↗
PubMed1990

Critically ischemic myocardium in clinically stable patients following thrombolytic therapy for acute myocardial infarction: potential implications for early coronary angioplasty in selected patients.

The utility of post-thrombolysis, rest-redistribution thallium (TI)-201 scintigraphy was studied in 32 patients with a first myocardial infarction who were clinically stable following reperfusion. Day 1 scintigraphy obtained 5 +/- 4 hours (range 1 to 16) after thrombolysis revealed an average perfusion defect of 6.5 +/- 2.6 segments (range 1 to 11). There was a total of 208 abnormal segments, 137 of which were nonreversible at 4 hours, 50 of which were fully or partially reversible, and 21 of which had a reverse redistribution pattern. Repeat TI-201 scintigraphy on day 10 revealed significantly smaller perfusion defects of 4.9 +/- 2.4 segments (range 0 to 9) with improvement predominantly of the day 1 reversible segments, and the improvement in segmental perfusion correlated with better regional left ventricular function. Twenty-nine (58%) of the 50 reversible segments normalized by day 10, and 11 (22%) improved, whereas only 16 (12%) of 137 nonreversible segments had normalized by day 10, only 9 had (6%) improved and 112 (82%) were unchanged (p less than 0.001 reversible versus nonreversible). There was no significant change in segments with a pattern of reverse redistribution. The improvement of reversible segments was greater in the 16 patients who underwent coronary angioplasty (PTCA) during the interval between the two scintigrams than in the 16 who did not. All 24 reversible segments in the PTCA group improved or normalized by day 10 compared with 16 (62%) of 26 reversible segments in the No PTCA group (p less than 0.001). Furthermore, 8 of the 10 reversible segments in the No PTCA group that did not improve actually deteriorated and became nonreversible by day 10. The minor improvement of nonreversible segments was not related to PTCA. Consistent with the findings in individual segments, the 19 patients with a reversible component on the day 1 TI-201 scintigram had significantly greater improvement in perfusion defect by day 10 than the 13 patients without a reversible component (37 +/- 33% versus 7 +/- 22% decrease in perfusion defect severity, p less than 0.05), and this improvement was greatest in the 10 patients with a reversible component who underwent PTCA. In contrast, PTCA had no impact on the perfusion defect in the 13 patients without a reversible component. Our data suggest that following thrombolytic therapy for acute myocardial infarction, viable myocardium in the reperfused zone may remain ischemic, as manifested by a reversible pattern of TI-201 redistribution at rest, and thus may be in jeopardy of gradual progression to necrosis.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1990

Does reperfusion extend necrosis? A study in a single territory of myocardial ischemia--half reperfused and half not reperfused.

The purpose of this study was to confirm or disprove the existence of reperfusion-induced extension of necrosis. To avoid the effect of the variability of collateral circulation when groups of dogs are compared, we compared the effect of reperfusion and nonreperfusion on myocardial necrosis in a single ischemic territory, half of which was reperfused and half of which was not. The left anterior descending coronary artery (LAD) territory between its last diagonal branch and the apex was studied because it was found to have uniform collateral blood flow. In 20 dogs, the LAD was occluded for 90-240 minutes to produce necrosis of different degrees of transmurality. Before release of this occlusion, the LAD was occluded distally halfway to the apex to keep the distal half nonreperfused. After 5 minutes of proximal reperfusion. Monastral blue dye was injected into the left atrium for demarcation of the reperfused region, and the heart was arrested, excised, cut parallel to the LAD, and placed into triphenyl tetrazolium chloride (TTC) solution for delineation of the region of necrosis. The validity of TTC staining under the conditions of this study was confirmed by light and electron microscopy. The transmurality of necrosis, measured within 1 or 0.5 cm on either side of the boundary, ranged from 30% to 88% of wall thickness and was not different in the reperfused compared with the nonreperfused region (paired t test). Reperfusion did not advance the epicardial edge of necrosis compared with the nonreperfused region. In conclusion, at 5 minutes after reperfusion, comparison of necrosis in the reperfused and nonreperfused halves of a single ischemic territory could not demonstrate an extension of necrosis by reperfusion.

Animals↗
PubMed1990

Bone mineral density after bicycle ergometry training.

The effect of functional electrical stimulation (FES) cycle ergometry on bone mineral density (BMD) was investigated in six spinal cord injury (SCI) quadriplegic men. Each subject trained three days a week for six months on an FES cycle ergometer. Pretraining and posttraining BMD measurements of the proximal femur were performed using dual photon absorptiometry. Mean pretraining BMD (percent norm) for the femoral neck, Ward triangle, and trochanter were 66.65, 57.43, and 57.67, respectively. After six months of FES cycle ergometry, mean BMD measurements were 66.15, 57.07, and 55.13, respectively. There was no statistically significant difference between the pretraining and posttraining BMD measurements. All subjects were found to have osteoporotic proximal femurs when BMD was expressed as a percent of their age-matched controls. Bone mineral density measurements were subsequently performed on three additional men with SCI who had exercised for three years with the FES cycle ergometry modality. Their mean BMDs were not significantly different from the experimental group. This study demonstrated that six months of FES cycle ergometry did not produce an increase in BMD.

Absorptiometry, Photon↗
PubMed1989

Selective decrease in lysis of old thrombi after rapid administration of tissue-type plasminogen activator.

The safety of thrombolytic therapy of acute myocardial infarction could be improved if a method were developed to dissolve fresh occlusive coronary thrombus without simultaneously dissolving hemostatic thrombi outside the coronary arteries. This study is based on the assumption that, in a patient with evolving acute myocardial infarction, hemostatic thrombi are likely to be older than the thrombus responsible for occlusion of the coronary artery. It explored whether the relative rates of lysis of fresh and old thrombi could be influenced by the rapidity of recombinant tissue-type plasminogen activator (rt-PA) administration. In each of 17 dogs, two 1 h and two 24 h old thrombi were produced by inserting copper coils into both jugular and both femoral veins. After 24 h and 1 h, respectively, the coils with the thrombi were removed, weighed and inserted into the adjacent carotid and femoral arteries. A 1 mg/kg body weight dose of rt-PA was given either over 180 or over 30 min. The coils were removed and weights of the residual thrombi determined at the end of the 180 min infusion (Group I), at the end of the 30 min infusion (Group IIA) and 45 min after the 30 min infusion (Group IIB). The 24 h old thrombi were lysed significantly less than the 1 h old thrombi in all three experimental groups: 53.9 +/- 4.8% (mean +/- SE) versus 86.1 +/- 2.5% in Group I (p less than 0.001), 16.6 +/- 3.5% versus 65.2 +/- 6.0% in Group IIA (p less than 0.001) and 21.6 +/- 5.4% versus 91.7 +/- 1.7% in Group IIB (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Exercise-induced ischemia in the streptokinase-reperfused myocardium: relationship to extent of salvaged myocardium and degree of residual coronary stenosis.

To assess the functional significance of residual stenosis at the site of the thrombolysed infarct-related coronary artery, 37 patients underwent exercise radionuclide ventriculography or stress-redistribution thallium-201 scintigraphy at an average of 7 weeks following streptokinase therapy during evolving myocardial infarction. The size of the initially jeopardized myocardium and the salvaged myocardium were quantitated on thallium-201 studies obtained immediately before and 10 days after streptokinase infusion. Exercise-induced ischemia (defined by reversible thallium-201 perfusion defects or stress-induced deterioration of regional wall motion) in the reperfused myocardium was absent in 46% of patients and was present in different degrees in the remaining 54%. A significantly lower proportion of patients, however, showed exercise-induced chest pain and/or ST segment depression (10% and 20%, respectively). By stepwise multiple logistic regression analysis, the quantitatively determined size of the salvaged myocardium (398 units versus 65 units, p less than 0.01) and the ratio of the salvaged myocardium/extent of initially jeopardized myocardium (70% versus 28%, p less than 0.01) were both independent predictors of stress-induced ischemia, whereas the extent of initially jeopardized myocardium (585 units versus 407 units, p = NS), incidence of greater than or equal to 99% coronary stenosis (37% versus 46%, p = NS), and ischemic time (160 versus 196 minutes, p = NS) did not provide additional predictive information. We conclude that exercise-induced ischemia, which is frequently present in the streptokinase-reperfused myocardium, cannot be detected accurately by exercise-induced chest pain or ST segment depression, nor can it be predicted by the severity of residual coronary stenosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗