2.1

Telecommunications technology

The evolution of currently used technology has been presented in more detail . In essence, the telecommunications system is based on a software application that can be downloaded to various commonly used platforms already available to first responders in the field, to caregivers at non-PCI capable hospitals, and to specialist physicians at a receiving institution. This software allows real-time, two-way voice and video capabilities to run over a secure HIPPA-compliant network, and provides the means for a direct contact with the interventional cardiologist on call who becomes involved from the initial stages of the STEMI management process.

With regard to the technical aspects of the application, video streaming is carried out using the Livecast™ video system (LiveCast, Vancuver, BC), which allows two-way video and audio transmissions from multiple sources and across multiple file formats, in addition to providing a way to manage and archive the individual interactions.

The implementation of this application in the care of patients imposes the need for fully secured video and voice interactions. In order to achieve a truly HIPPA compliant system, a virtual private network application (Columbitech™ mobile virtual private network, Stockholm Sweden), was adapted for our purposes to secure the video immediately for transmission. This software allows encryption to be integrated into the video streaming while permitting seamless access to a webcasting application without the need for additional hardware. In addition, the use of an efficient virtual private network permits a smooth transition from the wireless network to a mobile platform without interruptions to the livestream, as well as supporting its use on laptops and desktops connected to an institution’s pre-existing network ( Fig. 1 ).

Representation of the CHap software utilization.

With the integration of the Livecast™ video system and the Columbitech™ mobile virtual private network, a single turnkey application named “CodeHeart” was created in order to make it simple to install and very user friendly. The CodeHeart application (CHap) was designed by the MedStar Health Research Institute based on a grant from the Tauber Foundation and devised with the technical support of the AT&T™ (Dallas, TX) engineering department.

An initial pilot study first evaluated the potential use of this technology. Based on the initial results, subsequent development followed until its introduction into clinical practice.

2.2

Catheterization laboratory activation

CHap was first introduced in March 2011, and was evaluated immediately after its deployment over a well-established regional STEMI system of care comprised of multiple referral centers without PCI capabilities and a central receiving PCI-capable institution. The software application was downloaded to existing emergency room laptop and desktop computers in all participating centers, as well as those in the catheterization laboratories of the receiving hospital. Cellular video-phones (iPhone 3G smart phone™, Palo Alto, CA) equipped with the CHap were provided to regional ambulance teams and to interventional cardiologists involved in accepting patients with a possible ACS.

In the appropriate clinical scenario, a local caregiver directly contacted the interventional cardiologist at the PCI-capable hospital with the use of the CHap. Using the application, the care team briefly presented the case and showed the electrocardiogram to the interventional cardiologist on call. ( Fig. 2 ) Based on this interaction, both parties would then decide on the best management approach, which could include the activation of the catheterization laboratory for possible primary PCI or an elective inter-hospital transfer for subsequent observation or non-emergent PCI. When activation of the catheterization laboratory was considered appropriate, the on-call interventionalist activated the catheterization laboratory by contacting a central number where an expediter mobilized the entire team, and coordinated the transfer in the cases initiated at other institutions.

Screen shot of the CHap software being used on a mobile phone. It shows the image of the referring physician explaining the case and that of the electrocardiogram shown below.

After implementation of the CHap, all interactions using the system were recorded, and there were no exclusions. The interactions regarding a possible ACS were archived and subsequently matched to our institution’s ongoing database of catheterization laboratory activations. Matching involved date of intervention, timing of call, referral site, interventionalist involved, and interventional outcome. In addition, the accuracy of the matching details was confirmed against hospital admission and referral databases as well as quality databases at MedStar Washington Hospital Center and the MedStar Health Research Institute. CHap-generated activations were compared to those utilizing standard channels of activation over the same time period.

Of note, although the use of CHap was widely encouraged, previously established channels of activation persisted concomitantly and were more frequently used, especially during the initial months after deployment.

2.3

Data collection

Primary source documents for all events were obtained and used to adjudicate STEMI cases. Adjudications were performed by physicians unaware of the activation system utilized during a particular case. Quality measures pertaining to STEMI management and system performance were adjudicated by a centralized dedicated team not involved in the study.

The institutional review boards of MedStar Washington Hospital Center and the MedStar Health Research Institute (Washington, DC) approved this study. Experienced staff at a dedicated data-coordinating center performed all clinical data collection, entry, and analysis. Data regarding baseline clinical and procedural data, together with post-procedure inpatient events, were obtained from hospital chart review.

2.4

Study definitions

Electrocardiographic criteria defining a STEMI included the presence of at least 1 mm of ST-segment elevation in at least two contiguous leads, or the occurrence of a new left bundle branch block. A ‘true positive’ catheterization laboratory activation was defined as that in which a STEMI was adjudicated based on electrocardiographic criteria, and PCI or subsequent surgical revascularization was performed. ‘False positive’ catheterization laboratory activations were defined as those activations that did not meet electrocardiographic criteria for STEMI or those in which no revascularization was required.

The definition for DTB time was the time from first registered hospital contact to first intervention that restored blood flow to the culprit vessel. For transferred patients, DTB time was the time from first registered hospital contact at the outside institution as recorded on transfer records. Door-to-call was the time from hospital arrival to the first notification given to the interventional cardiologist on call. Call-to-lab was the time from initial call to arrival at the interventional suite. Call-to-balloon is defined as the time from initial call to the first intervention that restored blood flow to the culprit vessel. Door-to-EKG is the time from hospital arrival to first electrocardiogram considered to be STEMI qualifying according to preset criteria. EKG-to-call is the time from qualifying electrocardiogram to first call notification of a possible ACS. Other, more detailed parameters recorded in our institution were: Lab-to-balloon, representing time from catheterization suite arrival to first intervention that restored flow to the culprit vessel, lab-to-case start, as time from patient arrival to the interventional suite to time were first invasive action took place (generally initial stick) and case start-to-balloon as the time from first invasive action to first intervention that restored blood flow to the culprit vessel.

In-hospital major adverse cardiac events (MACE) were defined as the occurrence of death from any cause, Q-wave myocardial infarction (MI) or target lesion revascularization (TLR) before hospital discharge. Q-wave MI is defined as an elevation of creatine kinase-MB ≥3 times the upper normal value in the presence of new pathologic Q waves in ≥2 contiguous leads of the electrocardiogram. TLR is defined as clinically driven revascularization of the index lesion. PCI angiographic success is defined as a residual stenosis of <30% with thrombolysis in myocardial infarction grade III flow. Clinical success is defined as angiographic success plus the absence of TLR, Q-wave MI, or death prior to hospital discharge.

2.5

Interventional treatment

PCI was performed according to guidelines current at the time of the procedure. In all cases, the interventional strategy and the choice of peri-procedural and discharge medications were at the discretion of the responsible physician. Anticoagulation regimens included either bivalirudin 0.75 mg/kg followed by an infusion of 1.75 mg/kg/hour for the duration of the procedure or unfractionated heparin to achieve an activated clotting time of 200–300 seconds in all patients. All patients received an aspirin loading dose of 325 mg and were prescribed 81–325 mg once daily indefinitely. After a clopidogrel loading dose of 300–600 mg, patients were prescribed 75 mg once daily for ≥6 months in those who received a drug-eluting stent and ≥1 month in patients who received a bare metal stent.

2.6

Statistical analysis

Statistical analysis was performed using SAS version 9.1 (SAS Institute Inc, Cary, NC). Normally distributed continuous variables are presented as mean ± SD. Those variables not normally distributed are shown as median ± interquartile range. Categorical variables are expressed as frequencies and percentages. Baseline characteristics were compared using Student’s t test for parametric variables or the Mann–Whitney U test when not normally distributed. Categorical variables were compared using chi-square test or Fisher’s exact test as appropriate.

2.1

Telecommunications technology

The evolution of currently used technology has been presented in more detail . In essence, the telecommunications system is based on a software application that can be downloaded to various commonly used platforms already available to first responders in the field, to caregivers at non-PCI capable hospitals, and to specialist physicians at a receiving institution. This software allows real-time, two-way voice and video capabilities to run over a secure HIPPA-compliant network, and provides the means for a direct contact with the interventional cardiologist on call who becomes involved from the initial stages of the STEMI management process.

With regard to the technical aspects of the application, video streaming is carried out using the Livecast™ video system (LiveCast, Vancuver, BC), which allows two-way video and audio transmissions from multiple sources and across multiple file formats, in addition to providing a way to manage and archive the individual interactions.

The implementation of this application in the care of patients imposes the need for fully secured video and voice interactions. In order to achieve a truly HIPPA compliant system, a virtual private network application (Columbitech™ mobile virtual private network, Stockholm Sweden), was adapted for our purposes to secure the video immediately for transmission. This software allows encryption to be integrated into the video streaming while permitting seamless access to a webcasting application without the need for additional hardware. In addition, the use of an efficient virtual private network permits a smooth transition from the wireless network to a mobile platform without interruptions to the livestream, as well as supporting its use on laptops and desktops connected to an institution’s pre-existing network ( Fig. 1 ).

Representation of the CHap software utilization.

With the integration of the Livecast™ video system and the Columbitech™ mobile virtual private network, a single turnkey application named “CodeHeart” was created in order to make it simple to install and very user friendly. The CodeHeart application (CHap) was designed by the MedStar Health Research Institute based on a grant from the Tauber Foundation and devised with the technical support of the AT&T™ (Dallas, TX) engineering department.

An initial pilot study first evaluated the potential use of this technology. Based on the initial results, subsequent development followed until its introduction into clinical practice.

2.2

Catheterization laboratory activation

CHap was first introduced in March 2011, and was evaluated immediately after its deployment over a well-established regional STEMI system of care comprised of multiple referral centers without PCI capabilities and a central receiving PCI-capable institution. The software application was downloaded to existing emergency room laptop and desktop computers in all participating centers, as well as those in the catheterization laboratories of the receiving hospital. Cellular video-phones (iPhone 3G smart phone™, Palo Alto, CA) equipped with the CHap were provided to regional ambulance teams and to interventional cardiologists involved in accepting patients with a possible ACS.

In the appropriate clinical scenario, a local caregiver directly contacted the interventional cardiologist at the PCI-capable hospital with the use of the CHap. Using the application, the care team briefly presented the case and showed the electrocardiogram to the interventional cardiologist on call. ( Fig. 2 ) Based on this interaction, both parties would then decide on the best management approach, which could include the activation of the catheterization laboratory for possible primary PCI or an elective inter-hospital transfer for subsequent observation or non-emergent PCI. When activation of the catheterization laboratory was considered appropriate, the on-call interventionalist activated the catheterization laboratory by contacting a central number where an expediter mobilized the entire team, and coordinated the transfer in the cases initiated at other institutions.

Screen shot of the CHap software being used on a mobile phone. It shows the image of the referring physician explaining the case and that of the electrocardiogram shown below.

After implementation of the CHap, all interactions using the system were recorded, and there were no exclusions. The interactions regarding a possible ACS were archived and subsequently matched to our institution’s ongoing database of catheterization laboratory activations. Matching involved date of intervention, timing of call, referral site, interventionalist involved, and interventional outcome. In addition, the accuracy of the matching details was confirmed against hospital admission and referral databases as well as quality databases at MedStar Washington Hospital Center and the MedStar Health Research Institute. CHap-generated activations were compared to those utilizing standard channels of activation over the same time period.

Of note, although the use of CHap was widely encouraged, previously established channels of activation persisted concomitantly and were more frequently used, especially during the initial months after deployment.

2.3

Data collection

Primary source documents for all events were obtained and used to adjudicate STEMI cases. Adjudications were performed by physicians unaware of the activation system utilized during a particular case. Quality measures pertaining to STEMI management and system performance were adjudicated by a centralized dedicated team not involved in the study.

The institutional review boards of MedStar Washington Hospital Center and the MedStar Health Research Institute (Washington, DC) approved this study. Experienced staff at a dedicated data-coordinating center performed all clinical data collection, entry, and analysis. Data regarding baseline clinical and procedural data, together with post-procedure inpatient events, were obtained from hospital chart review.

2.4

Study definitions

Electrocardiographic criteria defining a STEMI included the presence of at least 1 mm of ST-segment elevation in at least two contiguous leads, or the occurrence of a new left bundle branch block. A ‘true positive’ catheterization laboratory activation was defined as that in which a STEMI was adjudicated based on electrocardiographic criteria, and PCI or subsequent surgical revascularization was performed. ‘False positive’ catheterization laboratory activations were defined as those activations that did not meet electrocardiographic criteria for STEMI or those in which no revascularization was required.

The definition for DTB time was the time from first registered hospital contact to first intervention that restored blood flow to the culprit vessel. For transferred patients, DTB time was the time from first registered hospital contact at the outside institution as recorded on transfer records. Door-to-call was the time from hospital arrival to the first notification given to the interventional cardiologist on call. Call-to-lab was the time from initial call to arrival at the interventional suite. Call-to-balloon is defined as the time from initial call to the first intervention that restored blood flow to the culprit vessel. Door-to-EKG is the time from hospital arrival to first electrocardiogram considered to be STEMI qualifying according to preset criteria. EKG-to-call is the time from qualifying electrocardiogram to first call notification of a possible ACS. Other, more detailed parameters recorded in our institution were: Lab-to-balloon, representing time from catheterization suite arrival to first intervention that restored flow to the culprit vessel, lab-to-case start, as time from patient arrival to the interventional suite to time were first invasive action took place (generally initial stick) and case start-to-balloon as the time from first invasive action to first intervention that restored blood flow to the culprit vessel.

In-hospital major adverse cardiac events (MACE) were defined as the occurrence of death from any cause, Q-wave myocardial infarction (MI) or target lesion revascularization (TLR) before hospital discharge. Q-wave MI is defined as an elevation of creatine kinase-MB ≥3 times the upper normal value in the presence of new pathologic Q waves in ≥2 contiguous leads of the electrocardiogram. TLR is defined as clinically driven revascularization of the index lesion. PCI angiographic success is defined as a residual stenosis of <30% with thrombolysis in myocardial infarction grade III flow. Clinical success is defined as angiographic success plus the absence of TLR, Q-wave MI, or death prior to hospital discharge.

2.5

Interventional treatment

PCI was performed according to guidelines current at the time of the procedure. In all cases, the interventional strategy and the choice of peri-procedural and discharge medications were at the discretion of the responsible physician. Anticoagulation regimens included either bivalirudin 0.75 mg/kg followed by an infusion of 1.75 mg/kg/hour for the duration of the procedure or unfractionated heparin to achieve an activated clotting time of 200–300 seconds in all patients. All patients received an aspirin loading dose of 325 mg and were prescribed 81–325 mg once daily indefinitely. After a clopidogrel loading dose of 300–600 mg, patients were prescribed 75 mg once daily for ≥6 months in those who received a drug-eluting stent and ≥1 month in patients who received a bare metal stent.

2.6

Statistical analysis

Statistical analysis was performed using SAS version 9.1 (SAS Institute Inc, Cary, NC). Normally distributed continuous variables are presented as mean ± SD. Those variables not normally distributed are shown as median ± interquartile range. Categorical variables are expressed as frequencies and percentages. Baseline characteristics were compared using Student’s t test for parametric variables or the Mann–Whitney U test when not normally distributed. Categorical variables were compared using chi-square test or Fisher’s exact test as appropriate.