Ionized calcium levels in coronary sinus blood during coronary angiography: effects of four contrast media.

The changes in ionized calcium level in the coronary sinus during coronary angiography were compared for four contrast media (meglumine sodium diatrizoate, iohexol, iopamidol, and meglumine sodium ioxaglate) in 44 subjects. Blood samples were collected before and 5, 15, and 30 seconds after injection of contrast medium into the left coronary artery. The hematocrit and ionized calcium level of each specimen were measured. Meglumine sodium diatrizoate produced the largest changes in hematocrit and ionized calcium level. The time-concentration curve of the hematocrit was similar for all four contrast media, but diatrizoate and ioxaglate produced a prolonged decrease of ionized calcium. The cause of this is not clear, but the phenomenon may be related to differences of ionic status among the contrast media. With respect to maintenance of the ionized calcium level, nonionic low-osmolality contrast medium with added calcium may be preferable for coronary angiography.     

Cardiac function during coronary arteriography with calcium enriched diatrizoate and metrizamide.

Calcium was added to diatrizoate (Renografin 76) and metrizamide (Amipaque) to concentrations from 2.5 to 50 mEq/1. The solutions were injected into the left coronary artery in dogs with either the chest opened or closed. In open chest experiments contractile force and aortic pressures were recorded. In closed chest dogs, left ventricular pressure, first derivative of that pressure and aortic pressure were registered. The calcium ion concentration was linearly, inversely related to the effect of the contrast solutions on the recorded parameters. In these experiments the optimal amount of calcium is suggested to 40 mEq/1 added to the diatrizoate solution but only 10 mEq/1 added to the metrizamide solution. No ECG changes due to calcium addition could be registered. The cardiac toxicity of these contrast media seem to be due to an interference with the calcium flux across the cell membrane. The effect on contractility can be recorded with the same reliability in either closed or open chest experiments.     

Caudal-posteroanterior view in coronary arteriography

Posteroanterior (PA) and caudally angulated PA views were obtained in 20 patients undergoing routine coronary arteriography. Although the left main coronary artery (LMCA) was seen well on both views in all patients, the PA-caudal view improved depiction of the LMCA bifurcation in 15 (75%). In addition, the PA-caudal view markedly improved depiction of the circumflex artery, affording optimal depiction of this artery and its branches in 78%-89% of patients. Neither the PA nor the PA-caudal view allowed adequate depiction of the left anterior descending artery. Thus, the PA-caudal view should supplant the PA view in routine coronary arteriography.     

Prostaglandin levels in human renal venous blood during renal arteriography

In view of the possible role of prostaglandins (PG) and thromboxane (TX) in the disturbances of renal function and blood flow after the injection of diatrizoate into the renal artery, we have determined the levels of PGE2, 6-keto-PGF1 alpha (a stable metabolite of prostacyclin) and TXB2 in the renal venous blood before, during and after renal arteriography in 12 patients. Radioimmunologically assayed PGE2 was the most abundant prostaglandin in renal venous blood. Lower basal levels of PGs were associated with renal adenocarcinomas or other tumours than non-tumour kidneys. The concentrations of 6-keto-PGF1 alpha and PGF2 alpha rapidly increased after diatrizoate injection and returned to the basal levels within 5 minutes. Slower elevation was noticed in the PGF2 level of 5 tumour kidneys. Renal plasma concentration of TXB2 remained unchanged throughout the study. The rapid elevation of renal venous prostacyclin and PGF2 alpha concentration after the contrast injection may reflect the enhanced intrarenal prostaglandin synthesis or may be secondary to hemodynamic changes in the kidney caused by hypertonic diatrizoate.     

烧伤后血与血钙浓度变化与补钙疗效分析

目的：寻找烧伤后血钙降低的规律与最佳补钙时机。方法：取烧伤后20天内的未补钙组与补钙一组和补钙二组各30例，进行组问对照。观察各组血钙及其它离子的变化。结果：三组血钙浓度均低于正常值(2．25mmol／L～2．75mmol／L)，但以未补钙组烧伤后血钙降低明显，第三天达最低值，持续时间与烧伤严重程度成正比，一般在伤后三周趋向恢复：补钙一组(连续5天补钙)血钙变化最小，补钙二组(隔日补钙10天)次之。结论：烧伤早期补钙可维持血钙浓度，早期连续补钙5天较隔日补钙10天效果为佳。     

The imaging of myocardial perfusion with 81mKr during coronary arteriography

The use of ^81mKr was investigated for imaging myocardial perfusion during coronary arteriography using conventional catheters. When the significance of stenosis judged by arteriography is unclear, the effect on tissue perfusion can be established and the contribution to collateral flow by each artery separately evaluated. The distribution of ^81mKr, due to its 13-s half-life, represents regional blood flow. In order to evaluate interventions, studies can be repeated at a low radiation risk to patients. A sterile pyrogenfree ⁸¹Rb–⁸¹Kr generator was developed. With slow infusion, inadequate mixing and streaming takes place due to laminar flow in coronary arteries. Fast intermittent 3-ml ⁸¹Kr-dextrose bolus injections convincingly eliminated streaming artefacts. Imaging was performed in 13 patients with a mobile scintillation camera and digital imaging system. Blood flow was calculated using the inert gas washout technique. There was good correlation (r=0.91) between coronary blood flow determinations using ^81mKr and ¹³³Xe respectively. The perfusion images correlated well with the coronary angiograms. Total coronary arterial occlusions as demonstrated by arteriography were all shown as perfusion defects during rest. During atrial pacing myocardial flow was increased two-fold in normal coronary arteries and to a lesser extent in arteries with significant disease. The most critical lesion in a branch of a left coronary artery leads to a redistribution of perfusion during pacing.     

Effects of contrast media on the RR and QT interval during coronary arteriography

During coronary arteriography, transient prolongation of the RR and QT intervals can be observed to occur. Animal experiments have suggested that low-osmolality contrast media have less effect, but there have been few clinical studies of this phenomenon. We analyzed 95 electrocardiographic records from patients who had undergone coronary arteriography and assessed the maximal prolongation of the RR and QT intervals. The contrast media used for arteriography included meglumine sodium diatrizoate, iopamidol, iohexol, and meglumine sodium ioxaglate. Diatrizoate caused the greatest electrocardiographic changes. Among the low osmolality contrast media, ioxaglate caused the smallest bradycardial effect and iohexol the smallest prolongation of the QT interval. It appears necessary to consider some additional factors for osmolality or ionicity, such as the chemotoxicity of the chemical structure of the iodinated contrast medium moiety, when assessing their potential adverse effect on the cardiac conduction system.     

离子钙水平与高血压性脑出血初始血肿量的相关性分析

目的：探讨离子钙水平与高血压性脑出血（HICH）初始血肿量的关系。方法：回顾性分析连续收治的88例HICH,收集血清总钙、离子钙、凝血功能等检查资料,并行脑血肿三维重建获取脑血肿体积。根据离子钙水平将患者分为2组：离子钙≤1.12 mmol/L为低离子钙组;>1.12 mmol/L为正常组。统计分析离子钙水平、凝血功能等与初始血肿量的关系。结果：入院时格拉斯哥昏迷指数（GCS）评分、血清总钙、初始血肿量在低离子钙组与正常组之间比较,差异均有统计学意义（均P<0.05）,而入院时血压、凝血功能等差异均无统计学意义（均P>0.05）。多元逐步线性回归分析显示,HICH初始血肿量与入院时血压、血清总钙、凝血功能、血小板计数等无相关性（均P>0.05）,与离子钙水平、GCS评分呈负相关（均P<0.05）。结论：离子钙水平与HICH的初始血肿量具有相关性,可反映病情危重程度。     

Effect of contrast media on left ventricular function during left coronary arteriography in dogs

The effect of contrast media on the left ventricular function of the heart was assessed by left coronary administration of contrast media using canine models. Following insertion of the catheter into the left coronary artery, 0.5 ml/kg of a test solution was injected at a rate of 1 ml/s. The test solutions included isotonic saline, meglumine/sodium diatrizoate, iopamidol and ioxaglate. The mean systemic pressure, left ventricular end-systolic and end-diastolic pressures and the first derivative of left ventricular pressure were continuously measured until five min post-injection. Left ventricular function decreased immediately by 15 s post-injection and recovered quickly by one min. The inhibition of myocardial contractility was observed with diatrizoate and ioxaglate to the same degree. These changes were statistically more pronounced than those with iopamidol, which showed changes similar to those with saline in all parameters except for the positive inotropic effects. These observations suggest that not only hyperosmolality but also ionic composition and chemotoxicity are the factors responsible for the myocardial depression and that no single factor dominates in their effects.