“We have piles of interface projects,” said William Weintraub, MD, FACC, chief of cardiology at Christiana Care (Wilmington, Del). “Every time we complete one project, we add two more to the list.”

Weintraub and Andrew Keller, MD, FACC, chief of cardiology at Danbury Hospital (Danbury, Conn), are co-chairs of the Integrating the Healthcare Enterprise (IHE) initiative for the cardiology domain.

“IHE really knits standards together,” explains Marla Wachtl, information technology manager at The Wisconsin Heart Hospital (Wauwatosa, Wis). “IHE is based on open standards, such as DICOM and HL7, but provides the bigger clinical picture and the wrapper around the standards to make them more usable. IHE is becoming much more relevant to cardiology.”

The Acuson Sequoia C512 flat-panel and echocardiology unit from Siemens Medical

IHE is a process designed to simplify the integration of clinical systems at hospitals and office practices. IHE provides mutually agreed upon (by vendors) technical specifications and independent testing facilities that would be virtually impossible for any site, even a large university, to duplicate.

The IHE cardiology domain was initiated in 2003 and is currently in Year 3 (2006?2007). “IHE Cardiology has come a long way in covering the breadth of cardiology services in Year 3,” Keller explains. “More of the cardiac subspecialties that are critical to every practice have been addressed, including nuclear medicine, stress-testing workflow, portions of electrophysiology, and additional electronic health record (EHR) integration efforts. These are in addition to Years 1 and 2, which included cardiac catheterization workflow and LVA/QCA measurements, echocardiography (ECG) workflow and measurements, ECG viewing, and report exchange.”

Stress-Testing Workflow Profile

Cardiac stress tests exhibit a variety of forms, with stress induced by treadmill, ergometer, or pharmacologically, and assessment of cardiac function made from ECGs and/or echo or nuclear imaging. If there are both ECG and imaging components to the study, they may be interpreted separately by different physicians.

Managing the ordering and performance of these varieties of stress tests is currently a process with many manual steps and duplication of effort. Electronic handling of orders, when it exists at all, rarely handles both the stress ECG equipment and the stress imaging equipment, requiring double entry of patient demographic data. Currently, few workstations can integrate both ECG data and imaging data for a consolidated view of the entire study for report preparation, requiring different side-by-side workstations and duplicated navigation to the patient’s data on each. If there are separate ECG and imaging reports, they often are handled by two different systems with no link between them.

This profile has defined, in detail, the HL7 admissions-discharge-transfer and order-details messages between the hospital information system (HIS), the order system, and a departmental cardiology information system. DICOM Modality Worklist, Performed Procedure Step, and Storage Commitment are used to get accurate and consistent patient demographic and order information all the way to the various clinical devices, whether it is the stress device itself, the echo cart, and/or the nuclear medicine camera. The IHE Cardiology Technical Framework also uses DICOM Waveform, Structured Report, and Encapsulated PDF objects to facilitate the interchange of data from the stress devices themselves.

The IHE Stress-Testing Workflow Profile provides the following specific benefits to cardiologists, administrators, and IT staff:

  • allows cardiologists to review stress-testing data and results at all points of care;
  • allows the management of stress results, both ECG and imaging, as a single coordinated data set;
  • allows the simple display of stress-test results and tracings on a variety of systems, including “generic” computers, allowing the cardiologist to review tracings acquired and interpreted elsewhere;
  • reduces the need for task- or modality-specific workstations in the patient care areas to review, collate, and correlate clinical information;
  • eliminates duplicate patient demographic data re-entry into multiple systems;
  • reduces errors (wrong patient data entered); and
  • integrates the complete set of clinical results into the patient’s EHR.

Nuclear Medicine Profile?Cardiology Option

“Today, very few general cardiology PACS solutions handle the transmission, storage, and display of cardiac nuclear medicine information adequately or correctly,” explains Peter Tilkemeier, MD, FACC, FASNC, associate professor, Brown University, and director of nuclear cardiology, The Miriam Hospital (Providence, RI). “Nuclear medicine is a critical element of cardiology; yet, many of these general cardiology solutions are completely unusable.”

A cardiac perfusion study.

The Nuclear Medicine (NM) Profile?Cardiology Option will allow the sharing of raw, processed, and quantitative images across many different settings and platforms. NM images present unique display requirements due to the color maps that are so critical to accurate interpretation. Also, a very specific American Society of Nuclear Cardiology (ASNC of Bethesda, Md) image-presentation method and reporting method is included in, and provides testing facilities for, IHE. Now, a physician in an office with system A could send images to the hospital for display on the PACS or for reprocessing on a different nuclear cardiology system. Conversely, the same physician could review a patient’s results from the hospital, facilitating prompt inpatient care or guiding the next decision for an outpatient. Prior to IHE, this interaction would have required the physician traveling to the information source to review the real images or to review a report only. With IHE, it becomes a comprehensive electronic interaction.

The NM Profile?Cardiology Option will allow a change in the way we consider equipment purchases. In the past, a major part of the decision has focused on the ability to integrate new equipment into the existing NM/nuclear cardiology network. This integration has usually been accomplished by picking the same vendor and locking in the technical developments that the vendor has implemented since the prior purchase. With this profile, it will be possible to integrate multiple vendors on the network. This will allow the purchaser to pick new equipment based on best of class, not on the last purchase decision.

This profile has defined the use of DICOM image objects to facilitate the interchange of data from the acquisition devices. It also defines considerable image-display requirements to ensure the accurate and consistent display of all types of NM images across various systems.

These images are from a stress test performed on a SPECT camera from Philips Medical.

The NM Profile?Cardiology Option has benefits for physicians, administrators, and IT staff that will:

  • allow cardiologists to review nuclear cardiology images—including raw data, reconstructed images, and quantitative displays—at all points of care;
  • allow the simple exchange of raw data, reconstructed images, and quantitative displays among different camera systems, enabling the cardiologist to review images acquired and processed elsewhere, or to reprocess them as necessary to meet the specific clinical need;
  • allow physicians to review nuclear cardiology images on generic workstations, supporting comparison of the data with other imaging modalities available on these workstations;
  • eliminate the need for multiple workstations for the patient care areas, reducing “monitor-megaly” for physicians who need to review several image types;
  • benefit the cardiology administrators by simplifying the purchasing process; and
  • benefit cardiology IT staff by easing the integration of various manufacturers’ equipment into the nuclear cardiology department, which will allow equipment decisions to be based on the best available technology rather than limiting the purchase choice to the current imaging-equipment supplier.

Electrophysiology Records to the EHR—Implantable Device Cardiac Observations

Recently, Medicare approved the reimbursement of implanted cardiac devices for the prevention of sudden cardiac arrest for a broader range of clinical indications. In other words, the number of these implanted devices (such as pacemakers, implantable cardioverter-defibrillators, and cardiac resynchronization therapy) is expected to increase rapidly.

Cardiac electrophysiologists follow patients with implantable cardiac devices from multiple vendors. These devices generate and store data about device identification, therapy settings, diagnostics, testing, and patient observations. As part of patient follow-up, an interrogation of the implanted devices is performed—either in clinic or remotely from the patient’s residence. Information is collected about the device, such as device identification, therapy settings, device diagnostics, and therapies delivered. These interrogations are performed by the vendor’s proprietary interrogation equipment, such as a device programmer or pacing-system analyzer.

Electrophysiologists require the access to key summary implantable rhythm control device interrogation information from a system such as an EHR. This profile defines specific data elements with specific data definitions as part of a method for the summary device interrogation information from the interrogation system to the information management system; the method is based on the Observation Results segment of HL7 (HL7-ORX). The profile also provides the mechanism to verify the accuracy of patient demographics as well as to identify patients across institutional settings.

The IHE Implantable Device Cardiac Observations (IDCO) Profile provides benefits to clinicians and administrative staff focusing on improving patient care and reducing inefficiencies, specifically by:

  • providing a standards-based format for the transmission of data from programmers, pacing system analyzers, and remote follow-up systems;
  • facilitating the transfer of data from multiple manufacturers’ equipment or remote follow-up systems into an EHR or other information system;
  • allowing a single information system to manage and display the data retrieved from multiple manufacturers’ equipment and remote follow-up systems; and
  • facilitating the transfer of data between EHRs/information systems.

Building a Cardiac PACS with IHE

Given the range of subspecialties that IHE Cardiology now addresses with the Year 3 Profile, it is possible to specify a general cardiology PACS solution that will meet the needs of most clinicians. When writing a request for proposal or contract, or during discussions with vendors, clinical users should consider the following IHE Cardiology Profiles and Actors for that PACS solution:

  1. Cardiac Catheterization Profile as the Image Manager, Image Archive, Evidence Creator, and Image Display Actors.
  2. Echocardiography Profile with Stress Echo Option as the Image Manager, Image Archive, Evidence Creator, and Image Display Actors.
  3. Nuclear Medicine Profile?Cardiology Option as the Image Manager, Image Archive, Evidence Creator, and Image Display Actors.
  4. Stress-Testing Workflow Profile as the Image Manager, Image Archive, Evidence Creator, and Image Display Actors.
  5. Scheduled Workflow Profile as the Image Manager, Image Archive, and MPPS Manager Actors.
  6. Evidence Documents Profile as the Image Manager, Image Display, and Evidence Creator Actors.
  7. Retrieve ECG for Display Profile as the Display Actor.

Next, each clinical site needs to determine whether it would like its cardiology PACS to operate as the repository for the ECG waveforms (in lieu of an ECG management system). If so, this site also should include “Retrieve ECG for Display Profile as the Information Source Actor.” (Note that the IHE does not include a billing component, which many ECG management systems do include.)

The Innova 2100 from GE Healthcare

Each clinical site needs to determine whether or not to incorporate an integrated Departmental Information System (such as scheduling, administrative statistics) as part of the cardiology PACS solution. If so, this site also should include the Department System Schedule/Order Filler Actor into each of the Workflow Profiles previously listed.

Each clinical site needs to determine where reporting and data-mining tasks will reside. If those tasks are to be part of the cardiology PACS, the Displayable Reports Profile Report Creator and Report Manager Actors also should be included.

Finally, if this cardiology PACS is to be integrated with an EHR system, the clinical site should include the Cross Enterprise Document Sharing (XDS), Cross Enterprise Document Sharing—Imaging (XDS-I), and Cross Enterprise Document Sharing Medical Summary (XDS-MS) profiles as the Document Source Actor.

It requires a time investment to research and understand the IHE, but it requires significantly more time to continue down the current piles of interface projects and to write use cases, technical specifications, and test plans and software (and hope it doesn’t break when the vendor upgrades the software)! For additional information, visit www.ihe.net or e-mail or .

Teri M. Sippel Schmidt is technical project manager of Integrating the Healthcare Enterprise?Cardiology for the American College of Cardiology (Bethesda, Md).