 Advertisement | ||||||||
 | ||||||||
|
||||||||
 |
 |
 |
 |
 |
 |
|
||
Electronic letters to:
|
|
Electronic letters published:
![[Read eLetter]](/icons/misc/sectionDOWN.gif){kind=icon}
Response to Dr Dery and de LaRocheliere
Early management of acute myocardial infarction depends of early diagnosis
Recent improvements in delays to reperfusion in Quebec City
|
|
|||
|
Thao Huynh Montreal General Hospital
Send letter to journal:
thao.huynhthanh{at}mail.mcgill.ca Thao Huynh
|
Response to Drs Déry and DelaLarochelière’s letter. We thank Drs Déry and DelaLarochelière’s for their comments and respond below to their concerns about the potential limitations of our results. First, we would like to address their remark that we concluded that “times to primary percutaneous coronary intervention (PCI) exceed current recommendations in most patients”. While only 8% of patients who underwent primary PCI with inter-hospital transfer were treated within recommended time delays, 36% of those treated on-site received therapy within recommended time delays. Therefore, at least in this latter group, time delays to primary PCI exceeded recommended time delays in many (but not most) patients. Drs Drs. Déry and DelaLarochelière were concerned that inclusion of several groups of patients may increase time delays to primary PCI including: (i) patients who present with atypical symptoms (such as patients who may have aortic dissection and pulmonary embolism) because of the time required to perform additional diagnostic studies;(ii) patients with initial non-diagnostic electrocardiograms (ECG), (iii) patients with contra-indications to fibrinolytic therapy, and (iv) patients who required intubation and cardio-pulmonary resuscitation because of required interventions for stabilization. To address these concerns, we undertook sensitivity analyses, in which we excluded the above patient groups. The results of these sensitivity analyses (see table) show that time to primary PCI remain prolonged even after exclusion of the above patients. Door-to balloon time delay (minutes) were: All patients: 109 (on-site PCI) and 142 (PCI with inter-hospital transfer) Excluding 9 patients with atypical symptoms and 7 patients with initial non-diagnostic ECG: 106 (on-site PCI) and 139 (PCI with inter- hospital transfer) Excluding 25 patients with contra-indications to fibrinolytic therapy: 109 (on-site PCI) and 146 (PCI with inter-hospital transfer) Excluding 84 patients who required cardio-pulmonary resuscitation, intubation, defibrillation before or during primary PCI: 102 (on-site PCI) and 137 (PCI with inter-hospital transfer) Excluding all of the above patients: 102 (on-site PCI) and 138 (PCI with inter-hospital transfer) Drs. Déry and DelaLarochelière were also concerned that we may have included patients who underwent rescue PCI. As the objective of our study was to measure time delays to initial reperfusion therapy (i.e. primary PCI and fibrinolytic therapy), we did not include patients who underwent rescue PCI. Only patients who underwent primary PCI without prior administration of fibrinolytic therapy were retained for analysis. Finally, “door-to-open artery” time is difficult to determine with accuracy, since the exact time when the artery opens is often unknown. This time delay, as proposed by Drs. Déry and DelaLarochelière, is relevant mainly among patients who already have an open artery prior to coronary intervention. In our study, 20% of patients had an open artery before any coronary intervention. In these patients, the median “door-to- open artery” time delay was 113 minutes (Q1,Q3: 76, 168) and 149 minutes (Q1,Q3: 107, 270) among those who underwent primary PCI on-site and with inter-hospital transfer, respectively. These times were similar to the door-to-balloon time delays reported in our study. We appreciate Drs. Déry and DelaLarochelière’s interest and do hope that these additional analyses and responses address the concerns raised. Huynh T, O'Loughlin J,Joseph L and Eisenberg M Conflict of Interest:Dr Huynh has received travel assistance from Roche Pharma Canada |
|||
|
|
|||
|
Jose Andres Calvache Medical Intern - Clinical Epidemiology Unit - University of Cauca, Colombia
Send letter to journal:
jacalvache{at}unicauca.edu.co Jose Andres Calvache
|
The actual guidelines for management of acute myocardial infarction (AMI) emphasize the early management with either fibrinolytic therapy or primary percutaneous coronary intervention. Nonetheless, early management depends of early diagnosis of AMI. Delays to therapy in AMI occur during 3 intervals: from onset of symptoms to patient recognition, during out-of-hospital transport, and during in-hospital evaluation. Patient delay to symptom recognition often constitutes the longest period of delay to treatment (1). For diagnosis of an acute ST-segment elevation myocardial STEMI, this study selected patients that presented suggestive symptoms of myocardial ischemia with a minimum duration of 20 minutes and an ST-segment elevation of at least 1 mm in 2 or more contiguous electrocardiogram leads or new left bundle branch block. The final diagnosis must have been confirmed by an emergency physician or cardiologist. However, is interesting the idea of that healthcare providers evaluate, triage, and treat patients with AMI as quickly as possible yet in the out-of-hospital setting (2). The public education campaigns related with the early recognition of AMI and early health systems activation could have benefical effects during the time of diagnosis an treatment. However, in any sites this campaigns increase public awareness and knowledge of the heart attack symptoms but have only transient effects (3). On the other hand, the results of this study show amazing differences between Canadian health system and others of developing countries like Colombia, where exist a lot of problems (administrative or logistics) that delay emergencies attention of patients. REFERENCES 1. Nallamothu BK, Bates ER, Herrin J, Wang Y, Bradley EH, Krumholz HM; NRMI Investigators. Times to treatment in transfer patients undergoing primary percutaneous coronary intervention in the United States: National Registry of Myocardial Infarction (NRMI)-3/4 analysis. Circulation. 2005;111:761-767. 2. 2005 American Hearth Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care: Part 8: Stabilization of the patient with Acute Coronary Syndromes. Circulation. 2005;112:IV-89-IV- 110. 3. Blohm M, Herlitz J, Schroder U, Hartford M, Karlson BW, Risenfors M, Larsson E, Luepker R, Wennerblom B, Holmberg S. Reaction to a media campaign focusing on delay in acute myocardial infarction. Heart Lung. 1991;20:661-666. Conflict of Interest:None declared |
|||
|
|
|||
|
Jean-Pierre Dery Quebec Heart and Lung Institute, Quebec City
Send letter to journal:
jean-pierre.dery{at}med.ulaval.ca Jean-Pierre Dery
|
In their manuscript on delays to reperfusion therapy in Quebec, Huynh et al. conclude that times to primary percutaneous coronary intervention (PCI) exceeds current recommendations in most patients. (1) We would like to highlight some limitations suggesting that these figures may be misleading. In their analysis, Huynh et al. did not exclude patients with explainable delays in making the diagnosis of ST-elevation myocardial infarction (STEMI). Some patients with suspected aortic dissection or pulmonary embolism may have undergone additional investigation prior to receiving reperfusion therapy. Also, it is not clear whether the authors excluded patients whose initial ECG was not diagnostic. A sizable number of acute coronary syndrome patients may develop clear ST-elevation only on a follow-up ECG while under observation in the emergency room. Patients with delayed diagnosis, contraindication to thrombolytic therapy and those who needed CPR, intubation or defibrillation may be more likely to receive primary PCI. These patients are expected to have longer delays to reperfusion therapy. In particular, it appears that patients transferred for primary PCI from distant hospitals because of contraindications to thrombolytic therapy have been included in the analysis. Also, the authors do not clarify whether patients referred for rescue PCI were included. These patients would obviously increase calculated delays to reperfusion therapy in transferred patients. Door-to-balloon time is not always the best indicator of treatment delay. In our institution we use door-to-open artery time to measure treatment delays. As many as 29% of ST-elevation patients will present with TIMI 2-3 flow in the culprit vessel on first coronary angiogram. (2) In these patients, the operator may voluntarily take time to perform a ventriculogram and additional coronary views, administer additional medications and/or use thrombus extraction catheter before performing coronary angioplasty. In these patients, door-to-open artery is a better assessment of reperfusion delay. Jean-Pierre Dery, MD, MSc, Robert DelaRochelière, MD Quebec Heart and Lung Institute, Hôpital Laval, Quebec City, Quebec, Canada 1. Huynh T, O'Loughlin J, Joseph L, Schampaert E, Rinfret S, Afilalo M, Kouz S, Cantin B, Nguyen M, Eisenberg MJ; AMI-QUEBEC Study Investigators. Delays to reperfusion therapy in acute ST-segment elevation myocardial infarction: results from the AMI-QUEBEC Study. CMAJ. 2006 Dec 5;175(12):1527-32. 2. Godicke J, Flather M, Noc M, Gyongyosi M, Arntz HR, Grip L, Gabriel HM, Huber K, Nugara F, Schroder J, Svensson L, Wang D, Zorman S, Montalescot G. Early versus periprocedural administration of abciximab for primary angioplasty: a pooled analysis of 6 studies. Am Heart J. 2005 Nov;150(5):1015. Conflict of Interest:Research Grant from Eli Lilly |
|||
| HOME | CURRENT ISSUE | PAST ISSUES | COLLECTIONS | HELP | SEARCH |
|
|||||
|
Copyright 1995-2010, Canadian Medical Association. All rights reserved. ISSN 1488-2329
(e) 0820-3946 (p)
All editorial matter in CMAJ represents the opinions of the authors and not necessarily those of the Canadian Medical Association. |
|||||
eLetters: