[Comments on the 2010 guidelines on cardiopulmonary resuscitation of the European Resuscitation Council]. / Kommentar zu den Leitlinien 2010 zur kardiopulmonalen Reanimation des European Resuscitation Council.

ADULTS: Administer chest compressions (minimum 100/min, minimum 5 cm depth) at a ratio of 30:2 with ventilation (tidal volume 500-600 ml, inspiration time 1 s, F(I)O2 if possible 1.0). Avoid any interruptions in chest compressions. After every single defibrillation attempt (initially biphasic 120-200 J, monophasic 360 J, subsequently with the respective highest energy), chest compressions are initiated again immediately for 2 min independent of the ECG rhythm. Tracheal intubation is the optimal method for securing the airway during resuscitation but should be performed only by experienced airway management providers. Laryngoscopy is performed during ongoing chest compressions; interruption of chest compressions for a maximum of 10 s to pass the tube through the vocal cords. Supraglottic airway devices are alternatives to tracheal intubation. Drug administration routes for adults and children: first choice i.v., second choice intraosseous (i.o.). Vasopressors: 1 mg epinephrine every 3-5 min i.v. After the third unsuccessful defibrillation amiodarone (300 mg i.v.), repetition (150 mg) possible. Sodium bicarbonate (50 ml 8.4%) only for excessive hyperkaliemia, metabolic acidosis, or intoxication with tricyclic antidepressants. Consider aminophylline (5 mg/kgBW). Thrombolysis during spontaneous circulation only for myocardial infarction or massive pulmonary embolism; during on-going cardiopulmonary resuscitation (CPR) only when indications of massive pulmonary embolism. Active compression-decompression (ACD-CPR) and inspiratory threshold valve (ITV-CPR) are not superior to good standard CPR. CHILDREN: Most effective improvement of outcome by prevention of full cardiorespiratory arrest. Basic life support: initially five rescue breaths, followed by chest compressions (100-120/min depth about one third of chest diameter), compression-ventilation ratio 15:2. Foreign body airway obstruction with insufficient cough: alternate back blows and chest compressions (infants), or abdominal compressions (children >1 year). Treatment of potentially reversible causes: ("4 Hs and 4 Ts") hypoxia and hypovolaemia, hypokalaemia and hyperkalaemia, hypothermia, and tension pneumothorax, tamponade, toxic/therapeutic disturbances, thrombosis (coronary/pulmonary). Advanced life support: adrenaline (epinephrine) 10 µg/kgBW i.v. or i.o. every 3-5 min. Defibrillation (4 J/kgBW; monophasic or biphasic) followed by 2 min CPR, then ECG and pulse check. NEWBORNS: Initially inflate the lungs with bag-valve mask ventilation (p(AW) 20-40 cmH2O). If heart rate remains <60/min, start chest compressions (120 chest compressions/min) and ventilation with a ratio 3:1. Maintain normothermia in preterm babies by covering them with foodgrade plastic wrap or similar. POSTRESUSCITATION PHASE: Early protocol-based intensive care stabilization; initiate mild hypothermia early regardless of initial cardiac rhythm [32-34°C for 12-24 h (adults) or 24 h (children); slow rewarming (<0.5°C/h)]. Consider percutaneous coronary intervention (PCI) in patients with presumed cardiac ischemia. Prediction of CPR outcome is not possible at the scene, determine neurological outcome <72 h after cardiac arrest with somatosensory evoked potentials, biochemical tests and neurological examination. ACUTE CORONARY SYNDROME: Even if only a weak suspicion of an acute coronary syndrome is present, record a prehospital 12-lead ECG. In parallel to pain therapy, administer aspirin (160-325 mg p.o. or i.v.) and clopidogrel (75-600 mg depending on strategy); in ST-elevation myocardial infarction (STEMI) and planned PCI also prasugrel (60 mg p.o.). Antithrombins, such as heparin (60 IU/kgBW, max. 4000 IU), enoxaparin, bivalirudin or fondaparinux depending on the diagnosis (STEMI or non-STEMI-ACS) and the planned therapeutic strategy. In STEMI define reperfusion strategy depending on duration of symptoms until PCI, age and location of infarction. TRAUMA: In severe hemorrhagic shock, definitive control of bleeding is the most important goal. For successful CPR of trauma patients a minimal intravascular volume status and management of hypoxia are essential. Aggressive fluid resuscitation, hyperventilation and excessive ventilation pressure may impair outcome in patients with severe hemorrhagic shock. TRAINING: Any CPR training is better than nothing; simplification of contents and processes is the main aim.

[The supraglottic airway in the prehospital setting]. / Der supraglottische Atemweg in der Prähospitalphase.

The supraglottic airway (SGA) is increasingly considered as a more effective alternative for emergency ventilation compared to bag mask ventilation and is propagated as an "easily" manageable method, compared to endotracheal intubation especially under the often adverse out-of-hospital conditions. Since the skill can easily be acquired during mannequin training, more and more rescue services train their personnel in the use of SGA devices and allow or even recommend their application also by nonphysicians. This recommendation, however, is not unequivocally supported by properly designed and conducted trials. Moreover, the solely available observational studies show contradictory results. Neither superiority nor inferiority of SGAs has been shown. They may, however, be accepted as an addendum to other prehospital ventilation approaches. The SGA airway comprises various problems and inherited risks similar to other ventilation techniques. Randomized studies investigating different techniques for prehospital emergency ventilation are lacking, as are controlled studies comparing SGA devices.

Phased chest and abdominal compression-decompression versus conventional cardiopulmonary resuscitation in out-of-hospital cardiac arrest.

BACKGROUND: Several methods have been developed to improve the efficacy of mechanical resuscitation, because organ perfusion achieved with conventional manual resuscitation is often insufficient. In animal studies, phased chest and abdominal compression-decompression resuscitation by use of the Lifestick device has resulted in a better outcome compared with that of conventional resuscitation. In end-of-life patients, an increased coronary perfusion pressure was achieved. The aim of the present study was to determine the feasibility, safety, and efficacy of the Lifestick compared with conventional resuscitation in patients with sudden nontraumatic out-of-hospital cardiac arrest. METHODS AND RESULTS: The crews of 4 mobile intensive care units, staffed by an emergency physician and a paramedic, were trained to use the device. Fifty patients were randomized by sealed envelopes to either Lifestick (n=24) or conventional (n=26) resuscitation. No differences were found regarding demographic and logistical conditions between the groups. Nineteen of the patients (73%) with conventional resuscitation had ventricular fibrillation, 13 of whom survived to hospital admission (no survivals with other arrhythmias) and 7 were discharged. In contrast, in the Lifestick-CPR group, only 9 patients had ventricular fibrillation (38%; P=<0.02; OR, 2.5; 95% CI, 0.6 to 10.6). Four of these 9 patients and 5 of 15 patients with other arrhythmias survived to hospital admission, but none survived to hospital discharge. Autopsy in a subgroup of patients who died at the scene revealed less injuries with Lifestick than with conventional resuscitation. CONCLUSION: Lifestick resuscitation is feasible and safe and may be advantageous in patients with asystole or pulseless electric activity.

Efficacy and safety of tenecteplase in combination with the low-molecular-weight heparin enoxaparin or unfractionated heparin in the prehospital setting: the Assessment of the Safety and Efficacy of a New Thrombolytic Regimen (ASSENT)-3 PLUS randomized trial in acute myocardial infarction.

BACKGROUND: The combination of a single-bolus fibrinolytic and a low-molecular-weight heparin may facilitate prehospital reperfusion and further improve clinical outcome in patients with ST-elevation myocardial infarction. METHODS AND RESULTS: In the prehospital setting, 1639 patients with ST-elevation myocardial infarction were randomly assigned to treatment with tenecteplase and either (1) intravenous bolus of 30 mg enoxaparin (ENOX) followed by 1 mg/kg subcutaneously BID for a maximum of 7 days or (2) weight-adjusted unfractionated heparin (UFH) for 48 hours. The median treatment delay was 115 minutes after symptom onset (53% within 2 hours). ENOX tended to reduce the composite of 30-day mortality or in-hospital reinfarction, or in-hospital refractory ischemia to 14.2% versus 17.4% for UFH (P=0.080), although there was no difference for this composite end point plus in-hospital intracranial hemorrhage or major bleeding (18.3% versus 20.3%, P=0.30). Correspondingly, there were reductions in in-hospital reinfarction (3.5% versus 5.8%, P=0.028) and refractory ischemia (4.4% versus 6.5%, P=0.067) but increases in total stroke (2.9% versus 1.3%, P=0.026) and intracranial hemorrhage (2.20% versus 0.97%, P=0.047). The increase in intracranial hemorrhage was seen in patients >75 years of age. CONCLUSIONS: Prehospital fibrinolysis allows 53% of patients to receive reperfusion treatment within 2 hours after symptom onset. The combination of tenecteplase with ENOX reduces early ischemic events, but lower doses of ENOX need to be tested in elderly patients. At present, therefore, tenecteplase and UFH are recommended as the routine pharmacological reperfusion treatment in the prehospital setting.

[Automated external defibrillators: perspectives and outlook]. / Frühdefibrillation: Perspektiven und Ausblick.

In Germany about 80.000 patients die of sudden cardiac death each year with enormous human, social and economic consequences. Most cases of sudden cardiac death are caused by ischemia-triggered ventricular fibrillation. A precondition for survival of the victims is an optimally and fast reacting "chain of survival". One of the central links of this chain is timely defibrillation, which is the only effective therapy for treatment of ventricular fibrillation. Automated external defibrillators proved to be a major step forward in improvement of resuscitation results. It has been convincingly demonstrated, that these devices not only are safe and efficacious in the hands of rescue personnel of different qualification degrees but also in the hands of minimally trained "first responders" and even in the hands of untrained lay people. This story of success was paralleled by the development of a new generation of biphasic defibrillators, which have a superior efficacy, are lightweight and are even cheaper than conventional devices. It must however kept in mind, that progress offered by these new opportunities will only translate in better resuscitation results, when programmes are thoroughly planned, will stay under continuous quality control with regard to performance of devices and rescuers and if new knowledge in resuscitation is adequately incorporated in action protocols.

[Prognostic assessment as the basis for limiting therapy in unconscious patients after cardiopulmonary resuscitation]. / Prognostische Einschätzung als Grundlage für die Therapiebegrenzung bewusstloser Patienten nach kardiopulmonaler Reanimation.

BACKGROUND: The prognosis of patients who have been resuscitated after cardiac arrest is still unfavourable and long-term results have only slightly improved. As a consequence, intensivists are frequently confronted with the question of limiting active therapeutic efforts for patients in prolonged coma. The history of the patient and circumstances of the resuscitation are of limited value with regard to reliable decisions. THERAPEUTIC DECISION-MAKING: Clinical and electrophysiological neurologic techniques as well as biomarkers and diagnostic imaging are, therefore, the basis for prognostication and potential consecutive therapeutic decisions. Sedation, relaxation and particularly therapeutic hypothermia have great influence on the test results. These influences have to be excluded before results can be validated. With regard to therapeutic hypothermia a reliable neurologic evaluation as a basis for limiting treatment is only possible after rewarming. Moreover results of multiple tests should be in agreement before a decision to limit treatment can be made. Finally it must be kept in mind that the absence of unfavourable test results is not proof of a good prognosis. CONCLUSION: The decision to limit treatment can not be made on the basis of a single adverse prognostic sign, but requires a comprehensive clinical diagnostic assessment.

Serum lipoprotein levels during long-term treatment of hypertension with indapamide.

The beneficial effect of antihypertensive pharmacotherapy in decreasing morbidity and mortality in hypertensive patients may be counteracted by metabolic and biochemical disturbances, such as hypokalemia, hyperglycemia, hyperuricemia, and hyperlipoproteinemia, that occur with the administration of thiazides and related diuretics. Antiatherogenic high-density lipoprotein cholesterol may be unchanged, whereas the potentially atherogenic low-density lipoprotein cholesterol may be increased by long-term therapy with thiazide diuretics. Indapamide is a methylindoline antihypertensive diuretic with a considerable peripheral vasodilatory effect. At a low dose of 2.5 mg daily, it did not alter total circulating cholesterol, in contrast to chlorthalidone. High-density lipoprotein cholesterol levels increased significantly in 20 hypertensive men after 6 months of therapy with indapamide, resulting in a significant fall of the low-density lipoprotein/high-density lipoprotein ratio, an atherogenic risk factor, regardless of preexisting lipid disorders.

Evidence for the benefit of early intervention with pravastatin for secondary prevention of cardiovascular events.

Treatment with HMG-CoA reductase inhibitors (or statins) lowers total and LDL cholesterol and decreases the risk of cardiovascular events. The absolute benefits are greater in patients with a higher baseline cardiovascular risk, so statins are particularly suited to secondary prevention. Although three large studies have shown convincingly that, in patients with a history of cardiovascular disease, simvastatin or pravastatin treatment reduces the risk of further events and lowers overall mortality, those studies have not included patients in the period immediately after an acute coronary event. They are, therefore, of limited value in answering the question of when to start statin treatment. However, there are practical reasons for starting statin treatment as early as possible, and results of clinical studies have now shown this to be a safe option for pravastatin. Early treatment with pravastatin can stabilize coronary atherosclerosis and improve endothelial function. More importantly, there is also evidence that early treatment with pravastatin can produce a clinical benefit a few months after the initial coronary event.

Studies of plasma viscosity in primary hyperlipoproteinaemia.

Using an Ubbelohde capillary viscometer, viscosity was determined in the plasma of 39 patients with a primary hyperlipoproteinaemia (type IIa, n=13; type IV, n=12; type IIb, n=14), in isolated lipoprotein fractions as well as in sera which differed only in their lipoprotein concentration. Plasma viscosity of the patients with hyperlipoproteinaemia was compared to that of a normolipidaemic control group and correlated with the lipid fractions characteristic of the different hyperlipoproteinaemia types. Plasma viscosity in types IIa, IV and IIb was found to be significantly higher than in the control group. Of the different hyperlipoproteinaemia types, IIa exhibited the lowest and IIb the highest plasma viscosity levels. The elevation of plasma viscosity was correlated with the concentration of lipoproteins (lipid fractions). In viscosity measurements of sera which varied only in lipoprotein concentrations, a correlation between the increase of viscosity and lipoprotein concentration as well as a greater efficiency of VLDL fractions was observed, similar to the viscosity results from isolated lipoproteins.

Efficiency of a physician-operated mobile intensive care unit for prehospital thrombolysis in acute myocardial infarction.

The efficiency of an emergency medical system for routinely performed prehospital thrombolysis is evaluated for 1 of the 7 physician-staffed mobile intensive care units (MICU) in former West Berlin. During 19 consecutive months the MICU had 4,920 missions, and 1,226 patients had chest pain of presumed cardiac origin. The diagnosis at hospital discharge was acute myocardial infarction (AMI) in 406 patients and "interrupted" infarction in 11 patients (total 417). Correct on-scene electrocardiographic diagnosis of acute injury was made in 268 patients (64%) and was false-positive in 4 patients (1%). In 8%, present ST elevations were not recognized. In 27%, the electrocardiogram on scene was nondiagnostic (16% with no ST elevation, 11% with bundle branch block). Of all 417 patients with later hospital evidence of AMI, 317 (76%) were seen by the MICU physician within 4 hours, and 173 (41%) within the first hour from symptom onset. Two hundred three patients seen within 4 hours had diagnostic ST elevation on the scene, of whom 124 (61%) received prehospital thrombolysis (74 patients [36%] within the first hour). There was no prehospital death; hospital mortality was 6.3%. Because greater than 50% of all patients in the community, hospitalized because of AMI, made use of the MICU and 3/4 of them had called within 4 hours from symptom onset, a large proportion of all patients with AMI were candidates for the actually received prehospital thrombolysis.

Beneficial effects of pravastatin (+/-colestyramine/niacin) initiated immediately after a coronary event (the randomized Lipid-Coronary Artery Disease [L-CAD] Study).

Secondary prevention of coronary heart disease by antilipidemic therapy beginning at > or =3 months after an acute coronary syndrome is well documented. The impact, however, of immediate initiation of antilipidemic therapy on coronary stenoses and clinical outcome in patients with acute coronary syndrome is unknown. In our study, patients were randomized, on average, 6 days after an acute myocardial infarction and/or percutaneous transluminal coronary angioplasty secondary to unstable angina, to pravastatin (combined, when necessary, with cholestyramine and/or nicotinic acid) to achieve low-density lipoprotein cholesterol levels of < or =130 mg/dl (group A, n = 70). In controls (group B, n = 56), antilipidemic therapy was determined by family physicians. Quantitative coronary angiography was performed at inclusion, and at 6- and 24-month follow-up. The combined clinical end points were total mortality, cardiovascular death, nonfatal myocardial infarction, need for coronary intervention, stroke, and new onset of peripheral vascular disease. Minimal lumen diameter in group A increased by 0.05 +/- 0.20 mm after 6 months and 0.13 +/- 0.29 mm after 24 months, whereas it decreased by 0.08 +/- 0.20 mm and 0.18 +/- 0.27 mm, respectively, in group B (p = 0.004 at 6 months and p <0.001 at 24 months). After 2 years, 29 patients of 56 patients in group B, but only 16 of 70 patients in group A, experienced a clinical end point (p = 0.005; odds ratio 0.28, confidence intervals 0.13 to 0.6). We conclude that pravastatin-based therapy initiated immediately after an acute coronary syndrome is well tolerated and safe, lessens coronary atherosclerosis, and has a pronounced clinical benefit.

Prehospital thrombolysis in acute myocardial infarction.

Efficacy of reperfusion therapy in acute myocardial infarction (AMI) is strictly time-dependent. Most benefit is achieved with initiation of therapy within the first 60-90 min after onset of symptoms. The majority of patients with AMIs are seen within this time window by emergency medical services. Moreover, average time gain of about 60 min is possible by prehospital thrombolysis. Randomized studies yielded a better outcome when a time gain of 90 min and more was achieved. Prehospital diagnosis of AMI is reliable. Moreover, out-of-hospital thrombolysis has no additional specific risks nor is it an obstacle for later percutaneous intervention. Consequently, patients seen within the first 60-90 min after onset of symptoms or for whom a time gain of 90 min or more can be expected should receive immediate prehospital thrombolysis.

Haemorheological changes in patients with retinal vein occlusion after isovolaemic haemodilution.

In 83 patients with central retinal vein occlusion and branch vein occlusion we measured the haematocrit (HCT), plasma viscosity (PV), red cell aggregation (RCA), red cell filterability (RCF) and apparent whole blood viscosity (WBV). A control group (n = 41) was matched for sex, age, and cardiovascular risk factors. Measurements were performed before and after treatment with isovolaemic haemodilution (IHD). We found no significant differences between patients with retinal vein occlusion (RVO) and control subjects in haematocrit, plasma viscosity, red cell aggregation, and red cell filterability and no increased whole blood viscosity in the patient group. Patients with ischaemic retinal vein occlusion and non-ischaemic retinal vein occlusion did not show different haemorheological parameters either. After treatment with haemodilution, only the haematocrit and whole blood viscosity were significantly decreased, and there were no changes in plasma viscosity, red cell aggregation or red cell filterability.

A randomised prospective study on treatment of central retinal vein occlusion by isovolaemic haemodilution and photocoagulation.

Thirty eight patients with ischaemic and non-ischaemic central retinal vein occlusion were evaluated for the effect of isovolaemic haemodilution. They were allocated at random to a haemodilution group (19 patients, panretinal photocoagulation and isovolaemic haemodilution) and a control group (19 patients, panretinal photocoagulation). Haematocrit was lowered in steps to 30 to 35% in the haemodilution group by repeated exchanges of whole blood for plasma and dextran (MW 40 000) and kept at this level for a period of six weeks. The haemodilution did not lead to serious complications. Three months after starting the treatment eight of 19 patients with haemodilution showed a better visual acuity, whereas only one of 19 control patients had improved. Seven of 17 patients with haemodilution, but only one of 17 control patients, retained a better visual acuity after one year. In the haemodilution group there were fewer patients with macular fibrosis and more with only minor foveal changes. The haemodilution seems to be more effective in patients with ischaemic than with non-ischaemic central retinal vein occlusion. It is concluded that isovolaemic haemodilution improves the visual outcome of patients with central retinal vein occlusion, probably mediated by enhanced retinal blood flow.

Establishment and results of an EMT-D program in a two-tiered physician-escorted rescue system. The experience in Berlin, Germany.

Early defibrillation by emergency medical technicians or even less qualified personnel has been shown to improve survival rates for out-of-hospital cardiac arrest caused by ventricular fibrillation. It has been questioned whether these favourable results can be applied within the context of physician-attended emergency medical systems. Taking into consideration the results of a pilot study and after a careful analysis of the logistic and epidemiological background, the first German EMT-D program was introduced in the former West Berlin in December 1988. The first 2 years of experience with 499 technician-initiated resuscitation attempts in which the mobile intensive care unit of Klinikum Steglitz was involved, confirmed the results of the pilot study with an improved long-term survival rate (18%) for patients with ventricular fibrillation. We conclude that EMT defibrillation should be introduced in emergency physician-attended two-tiered emergency medical systems, whenever a thorough analysis of the existing rescue systems exhibits a 'relevant frequency' of resuscitation and response interval of 15 min or less.

Failure to show a correlation between serum parathyroid hormone, nerve conduction velocity and serum lipids in hemodialysis patients.

The proposed role of parathyroid hormone as an important agent for the development of certain uremic complications could not be confirmed in studies correlating, in dialysis patients, the nerve conduction velocity and the serum lipids with four different immunochemically defined forms of circulating parathyroid hormone. To a certain extent the data invalidate suggestions which favor parathyroid hormone as a leading uremic toxin.

Prehospital thrombolysis in acute myocardial infarction.

Efficacy of reperfusion therapy in acute myocardial infarction is strictly time dependent. As is evidenced by several studies, most benefit in terms of myocardial salvage and short- and long-term mortality is achieved with initiation of therapy within the first 60-90 minutes after onset of symptoms. Nearly exclusively, prehospital initiation of thrombolysis makes it possible to take advantage of this early time window. Moreover a time gain of more than 30 minutes, up to 130 minutes, is possible by prehospital initiation of thrombolysis, depending on local circumstances. Randomized studies yielded a better outcome when a time gain of > or = 90 minutes was achieved. Since it has been shown that prehospital diagnosis of an acute myocardial infarction is reliable and out-of-hospital initiation of therapy has no additional specific risk, patients seen within the first 60-90 minutes after onset of symptoms or for whom a relevant time gain of > or = 90 minutes can be expected are ideal candidates for, and therefore should receive, prehospital thrombolysis.

Long-term prognosis of cardiovascular patients following mobile emergency care.

Mobile emergency care units provide immediate benefit for patients with acute cardiovascular disease, but the subsequent prognosis of this patient population is unclear. We, therefore, aimed to determine whether the long-term survival of patients with acute cardiovascular syndromes requiring emergency medical care differs from controls of the general population. The long-term survival was analysed in all consecutive patients who were treated for acute cardiovascular events (coronary syndromes/cardiac arrest, pulmonary oedema, stroke, vascular disorientation/unconsciousness) by a mobile emergency care unit or rescue helicopter in Berlin from 1987 to 1988 and were admitted to hospital. Subsequent mortality follow-up information was obtained throughout 1994 from medical records and official vital statistics. The survival of the patient population was compared with standardized mortality data of controls matched for gender, age, and residential location. A total of 1206 patients (48% men, 67 +/- 14 years, 52% women, 72 +/- 17 years) were included in the analysis. The 1-year survival of the patient population was significantly lower compared with controls (76% vs. 88%, p < 0.001), but during subsequent years this difference was continuously reduced. Seven years after the initial event, survival rates of patients and controls were similar (43% vs. 41%). The results were similar in both gender groups. Patients > 65 years of age had a markedly higher mortality compared with patients < or = 65 years, as would be expected. Older patients had a similar long-term survival compared with controls (27% vs. 28%), whereas younger patients sustained a relatively lower long-term survival compared with controls (75% vs. 86%, p < 0.05). It is concluded that a novel population-based approach demonstrates similar long-term prognosis of cardiovascular patients following mobile emergency care compared with matched controls. The present results may contribute to the assessment of long-term effectiveness and the appropriate design of emergency care systems.

[3-D localization of cardiac structures in real time]. / 3-D-Lokalisation kardialer Strukturen in Echtzeit.

Radiographic 3-D localisation enables measurements to be made that facilitate the placement of the interventional device during cardiac intervention. To enable the reader to implement the method himself, we describe the computation of 3-D coordinates, acquisition of the imaging and projection data on-line, and the accuracy that can be expected with the method. The 3-D coordinates of a cardiac structure are calculated from the image point coordinates, the projection data and the system constants of a biplane isocentric X-ray unit. Technical imaging errors are corrected a priori. The biplane projection data of a run are acquired on-line and stored in a data base. The image pair of interest is identified automatically from the inscribed run number, and assigned to the projection data from the data base. The target image point is marked on the monitor for 3-D localisation. The accuracy of the method was determined by comparing the calculated and actual cross-sectional points of a centimetre grid imaged in biplane X-ray projections. 3-D localisation took an average of 9.8 +/- 1.2 seconds. Angles and distances were assessed with a standard error of 1.1 degrees and 0.8 mm. The run number is identified correctly in 98.5% of the cases. The mean absolute location error for all points and image pairs was 0.61 +/- 0.32 mm. The accuracy and precision was 0.03 +/- 0.40 mm. Radiographic 3-D localisation can be performed readily and accurately on-line. The results obtained with the method enable interventional decisions to be optimized.

[Development and validation of a graphic method for spatial interpretation and evaluation of biplanar coronary angiograms]. / Entwicklung und Validierung eines graphischen Verfahrens zur räumlichen Interpretation und Bewertung biplaner Koronarangiogramme.

Visual evaluation and measurement of the lesion geometry is impaired by the foreshortening of the radiographically displayed target coronary segment. For this reason, we developed and validated a simple graphic procedure that facilitates the spatial interpretation and allows an objectifiable assessment of the view of the target coronary segment. The method computes a spatial axis of the coronary segment imaged in two planes and determines its inclination in the radiation path of each projection view. A triangle made up of the axis of the imaged segment, the unforeshortened axis of the imaged segment and the foreshortening height is displayed in each projection plane. The shape of the triangle indicates the degree of foreshortening while its position in the angiogram indicates the orientation of the spatial axis relative to the observer. The method was validated by comparing calculated and true foreshortening in the radiographic views of a centimetre grid obtained in the usual angiographic projections. The method has an accuracy and precision of 0.05 +/- 0.62%. It is applied clinically to evaluate biplane segmental visualization during coronary interventions and to select valid segmental views for measurements during quantitative biplane coronary angiography. This application may considerably facilitate the interpretation and assessment of biplane angiograms.