NIC Companion Book of Interventional Cardiology Rishi Sethi, Narendra Nath Khanna, J Shiv Kumar
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Good Clinical Practices in Cath Lab1 CHAPTER

Rishi Sethi,
Akshyaya Pradhan,
J Shiv Kumar
‘From inability to let well alone; From too much zeal for the new and contempt for what is old; From putting knowledge before wisdom, science before art, and Cleverness before common sense; From treating patients as cases; And from making the cure of the disease more grievous than the Endurance of the same, Good Lord, deliver us.
–Sir Robert Hutchison
 
INTRODUCTION
The spectrum of cardiac catheterization has gone a paradigm change from mere diagnostic evaluation of pressure waveform to complex transcatheter coronary, structural and electro-physiological therapies. It goes without saying that cardiac catheterization laboratory (or Cath Lab as commonly referred to) is a vital arena in management of patients with heart disease, saving millions of life in both emergency and elective setting alike. A cardiac event is usually an important turning point in a patient’s lifetime and often the support and confidence instilled by the hospital can go a long way in his rehabilitation. With the huge leap in the number of patients undergoing procedures in Cath Labs, there is an imperative need on regulation of quality of procedures too. There can be no universal definition of the “Good Samaritan” but only a consensus from evidence, eminence and experience (Table 1.1).
Table 1.1   Ten commandments of good Cath Lab practices
  • Communicate freely and encourage others to do so
  • Ensure a comprehensive pre-procedure checklist
  • Never fail to obtain a well written and informed consent
  • Always perform a “time out” on table
  • Involve the whole team and its attention when patient is on table
  • Double check medications before administering
  • Do not forget-RADSAFE and Sharps for your own safety
  • The procedure is over but your job is not- access site and monitoring
  • Physician—Teach, train and be ready for review
  • Emphasis on building a good team work approach
 
THE TEAM APPROACH
The physician is the captain of the whole Cath Lab team. He may be assisted by a variable team compromising of assistant physicians, resident(s), certified technicians, nurses and other support staff. It is the duty of physician to delegate and define clearly the duty each member of team according to the local protocol.
Typically, two-three people are tableside whereas as two additional are in “circulating” or “monitoring” role. Performing cardiologists must be adequately trained and credentialed whereas as tableside assistants must be well-versed in manifold setup, automatic/power injection and sterile techniques. The Cath Lab should have proper record maintenance of all cases including outcomes and complications.
There should be at least weekly conference of whole team where various aspects of 2 procedures, viz. indications, complications, recent advancements, pharmacotherapy, new hardware are discussed. The physician and technical staff should be encouraged to engage in continuing medical education activities as per national/state medical board requirements. The physician also should hold regular quality control and peer review meetings with other institutes for appropriateness assessment. All staff must have full training in cardiopulmonary resuscitation (BLS and ALS certification) from American College of Cardiology/American Heart Association (ACC/AHA) or equivalent. For high-risk cases and cases needing deep sedation an anesthesiologist should be on board.
 
COMMUNICATION: ENCOURAGE THE CULTURE TO SPEAK-UP
Appropriate communication of physician with his patients and team members is the backbone for effective functioning of any lab. The physician or one of his team members should effectively communicate with the patient and relatives about all aspects the procedure both before and after.
The team members should have clear channels of communications amongst themselves. Informing the performing physician about the clinical status of his patients allows him to triage patients and avoid delays in Cath Lab arrival. The physician on the other hand should inform the team in advance the destination for shifting the patients and special equipment needed.
All orders given by physician during procedures should be loud and clear. The performing staff should acknowledge back receipt and performance of task loud and clear too. The physician on table may acknowledge procedure steps to keep whole staff in loop like “heparin being given”, “lesion being dilated”, “heart rate is stable” and so on. All communications should be documented in records as far as practical.
The co-workers should be encouraged to speak up without fear on issues that might seem unpleasant. This allows them to accept mistakes and take corrective measure rather than hide things and put the patient in jeopardy, e.g. heparin not been given. Sometimes pertinent suggestions or warnings from an assistant can make the operator take note of relevant things he might be ignoring.
 
Before the Table
Five essential steps in this phase are— Documentation of Indications, Focused examination, Consent, Checklist and Sedation.
 
Indications and Examination
Upon reception of patient in preprocedure lounge, give some time to discuss the indications and details of the procedure with him in a professional manner. Avoid loose and also highly technical terms.
A brief history and focused physical examination pertinent to cardiovascular system and local access site are in order too. Careful examination to detect signs of heart failure will lead to prophylactic diuretic administration and use of noninvasive positive pressure ventilation (NIPPV) during procedure.
Helpful targets of history could be allergies, barriers to long-term antiplatelets, anticoagulant use, previous medication compliance, etc. Documentation of above mentioned chores is a wise step and legally sound too.
 
Informed Consent
In this era of “Dr Google” and medicolegal awareness, a written and informed consent is a sine-qua-non. Explain the patient in simple and realistic terms what he can hope achieve from the procedure and what he cannot. The attendant risks of procedure and need for further management from diagnostic procedures need to be explained as well. It is helpful to have one relative of the patient during the discussion. The information must be in patient’s native language and signed by patient as well as the witness (relative).
 
Checklist
A preprocedural checklist is an essential document in any Cath Lab or surgical suite. The importance of checklist has been already been proven in large population and hospital-based studies. What a checklist does apart from reducing human errors is cognitive reinforcement! It puts the spotlight back on patient safety and ensures all steps are done reliably. Continued use of checklist can induce positive behavioral changes in members of Cath Lab team.
3Although it can be tailored to local needs but quintessentially should include blood investigation review, periprocedural antiplatelet and antithrombotic review, bleeding risk, contrast-induced nephropathy (CIN) risk, etc.
Blood investigations should include complete blood count, electrolytes, renal profile, blood sugar as bare minimum. For outpatient setting investigations performed within the previous month are relevant if there has been no change in hemodynamic status. In an in-hospital setting, investigation must be obtained within previous 24 hours. Significant anemia (Hb < 9.0 g%) needs to be corrected before attempting percutaneous coronary intervention (PCI) or when dual antiplatelets are contemplated. A low platelet count could prompt the use of bivalirudin.
Relook at the baseline ECG reaffirms the expected coronary artery anatomy, hemodynamic status and comparison with changes occurring postprocedure too.
At this juncture, the calculation of various risk scores is highly advisable.
Antiplatelet and low molecular weight heparin dose as well as timing should be reviewed. Patients on chronic anticoagulation need an INR estimation. Values greater than 1.8 and 2.2 preclude cardiac catheterization by femoral and radial routes respectively. A brief review of drug or contrast allergy from previous exposure should be documented. A protocol of steroids and antihistaminic suffices to prevent contrast reactions and is widely practiced.
In females, assessment of childbearing status is essential. Last minute check on patency of IV lines should be ensured as well as documented. A prototype checklist is enclosed for reference (Fig. 1.1).
 
Sedation and Anxiolytics
The use of sedation or anxiolytics is choice of local Cath Lab team. The increased use of radial access has again rekindled interest in conscious sedation. The 2012 Society for Cardiovascular Angiography and Interventions (SCAI) consensus document on best practices in Cath Lab advocates use of conscious sedation and mandates that physicians demonstrate proficiency in sedation pharmacology as well as airway management. Premedication with oral diphenhydramine and diazepam is common. A combination of midazolam and fentanyl citrate is another popular option. Caution is needed to avoid over sedation. Keeping the patient Nil per oral for 8 hours is mandatory if sedation is planned otherwise a 3–4 hours fasting is adequate routinely.
 
Diabetic Patient
Diabetic patients need to be watched for hypoglycemia. The insulin dose should be reduced by half on the previous night and withheld on the morning of the procedure. Oral hypoglycemic agents should also be withheld on the day of procedure.
Diabetic patients should be scheduled early whenever feasible, to avoid hypoglycemia. Metformin should be withheld regardless of the creatinine clearance and not restarted 48 hours postprocedure.
 
Never Forget to Calculate the Risk
A risk score brings objectivity and clarity both in the operator’s and patient’s thought process regarding the quantum of risk expected. This coupled with the mortality and symptomatic benefit of the intended procedure leads to accurate risk benefit estimation justifying the procedure both scientifically and medicolegally. They also present an opportunity to identify and triage the “High Risk” patient who will benefit from implementation of additional corrective measures and safeguards like the route of access, hemodynamic support, periprocedural drugs etc. The risk scores useful in the lab can be broadly classified into three groups—the risk of disease itself, the overall risk of procedures and the risk of major complications like bleeding, CIN, etc. (Fig. 1.2).
ST-elevation myocardial infarction itself portends very high risk and do not practically require specific risk estimation. Non-ST elevation myocardial infarction (NSTEMI) and unstable angina (USA) however, represent a spectrum and need risk stratification to decide upon timing of invasive therapy. The European guidelines advocate the use of Global Registry of Acute Coronary Events (GRACE) risk scoring system to evaluate risk both at admission and discharge accurately.4
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Fig. 1.1: A sample checklist to be used preprocedure in the cardiac catheterization suite
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Fig. 1.2: Summary of risk estimation scores
The newer GRACE 2.0 risk calculator uses multiple variables like—age, systolic blood pressure, pulse rate, serum creatinine, killip class on admission, cardiac arrest at admission, elevated biomarkers, serum creatinine and ST-segment deviations. Diuretic use and renal failure can substitute serum creatinine and killip class when data regarding the latter are not there. It provides a direct estimation of mortality during hospital stay, at 6 months, 1 year and 3 years. Thrombolysis in myocardial infarction (TIMI) risk uses seven simple variables—age, asprin use in past week, elevated cardiac biomarkers, >3 classical CAD risk factors, >2 anginal episodes within last 24 hours, ST-depression > 0.5 mm and established CAD. Despite being easy and popular score for risk stratification in acute coronary syndromes (ACS), its discriminative accuracy is inferior to GRACE score.
The procedural risk is easily identified by either one of comprehensive scores like Syntax, Clinical Syntax, NCDR Cath PCI risk or simple one’s like ACEF risk score.
The age, creatinine and ejection fraction (ACEF) is a very simple model and has been validated to predict mortality in patients undergoing PCI. The SYNTAX score uses eleven coronary anatomical complexity variables to predict major adverse cardiac events in multivessel coronary artery disease (CAD) patients undergoing PCI. The SYNTAX score derivatives like clinical SYNTAX and SYNTAX II add clinical variables (like age, election fraction, creatinine clearance, etc.) to the existing anatomical ones and have shown superiority in predicting long-term outcomes.
Bleeding events also increase mortality following cardiac catheterization (especially PCI). Two bleeding scores CRUSADE and ACUITY have been developed from trials and registry models. The Can Rapid risk stratification of Unstable angina patients Suppress ADverse outcomes with Early implementation of the ACC/AHA guidelines (CRUSADE) bleeding risk score uses—baseline patient characteristics (i.e. female gender, history of diabetes, history of peripheral vascular disease or stroke), admission clinical variables (i.e. heart rate, systolic blood pressure, signs of heart failure) and admission laboratory values (i.e. hematocrit, calculated creatinine clearance) to estimate likelihood of an in-hospital major bleeding event. The Acute Catheterization and Urgent Intervention Triage strategY (ACUITY) bleeding risk score utilizes six baseline predictors (i.e. female gender, advanced age, elevated serum creatinine, white blood cell count, anemia and presentation as NSTEMI or STEMI) and one treatment related variable [use of unfractionated heparin (UFH) and a glycoprotein IIb/IIIa (GPIIb/IIIa) inhibitor rather than bivalirudin alone]. This system identifies patients at increased risk for non-CABG-related major bleeds at 30 days and subsequent 1 year mortality. Though, both scores have good accuracy in prediction of major bleeding events, CRUSADE score is more discriminatory and hence recommended by guidelines. Use of radial access, reduction in the dose of UFH, use of bivalirudin, diminished use of GPIIb/IIIa inhibitors and administration of more potent inhibitors of P2Y12 are some measures that may prove to be game changers in mitigating bleeding risk following coronary angiography and PCI in high bleeding risk. Contrast-induced nephropathy (CIN) is also an avoidable complication. A risk score developed by Mehran et al. uses—age, anemia, hemodynamic instability, congestive heart failure presence, hypotension, contrast volume, diabetes mellitus, intra-aortic balloon pump use and eGFR to forecast risk of CIN and dialysis postprocedure. A score of 16 of more indicates >50% risk of CIN and 12.6% risk of dialysis while values between 11 and 16 peg the risks at 26 and 1.1% respectively.
 
On the Table
 
Time Out
With the work volume of cardiac Cath Labs having upward trend, the importance of time out cannot be overemphasized. After patient is on table, 6 a team member must identify and announce the patient in front of other members. Identity must be established by at least two variables because it is not uncommon to have two patients of similar names in the cath list of a busy Cath Lab. It is useful also to declare the intended procedure, access, hardware needed and special medical condition of interest, if any. Time out should occur just before vascular access.
 
Patient Preparation and Access
After the patient is on table, ECG monitoring followed by IV line attachment should be established as a first of things. Other ancillary monitors will vary according to local protocols.
Complete aseptic precautions while draping the patient are must. Chlorhexidine-based antimicrobial agents and drapes that adhere to skin around access site are useful companions. Ensure that the drape covers whole table extending all way up to patient’s upper chest. Sterile objects should move only from one sterile area to other. As a rule no unsterile object should move over the sterile field. Always avoid movement of staff between equipment trolley and patient table and touching of ends of sterile objects (catheter, tubes, needles) by unscrubbed personnel.
 
Radiation Safety
It is matter of concern that interventional cardiology now accounts for up to 50% of total effective dose by radiation in medical imaging in western world. It also now well-understood that detrimental effects of radiation can be both dose dependent (deterministic) and independent (stochastic). Hence, every effort must be made for protection of patient and radiation workers. The major source of radiation for Cath Lab workers is scattered radiation from patient.
All staff must wear lead apron and thyroid shields whereas the operators on table should wear additional lead glasses as a bare minimum. Measure to decrease radiation to patient include-low frame rates, less “beam on” time, use of pulse fluoroscopy, limiting cineangiography acquisition, save fluoroscopy image data (fluoro store), collimation use (collimate), avoid unnecessary magnification (low mag), copper or other filter use at output (filters on), avoid extremely angulated views, minimize source to image distance (eye down), limiting runs and finally avoid working exclusively in a particular view. Tracking and measuring of radiation dose for all staff is mandatory via individual badges.
The maximal allowable radiation dose for medical worker is 50 millisieverts per year for whole body. If a patient gets any radiation dose exceeding six grays he should be informed of potential skin burn and followed up. Simple measures for additional protection are outlined in Figure 1.3. These measures when used properly are effective in reducing the scatter radiation in reaching operators body by more than 90%.
 
Universal Precautions
Use of head caps, facemask, shoe covers, double gloving and protective eye wear are core elements of universal protection. Double gloving has been shown to reduce the chances of a puncture hole in the inner glove by 60%. Extracare should be taken to avoid splashing of blood in any form. All solution to be used in procedure are to made in real time at bedside and clearly labeled. Double check medications before administering them. Proper disposal and disinfection methods should be adhered to and reviewed regularly. All devices used in infected (HIV or Hepatitis) patients are to be discarded immediately after procedure and time for adequate cleaning of lab post procedure to be ensured.
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Fig. 1.3: Key elements of radiation safety depicted by pneumonic “RADSAFE”
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Figs 1.4A and B: Simple measures to prevent sharp objects injury in Cath Lab. (A) Avoid recapping needle in air or while holding them in hand; (B) All sharp objects to be collected in single area (kidney tray) during procedure
 
Sharp Protection
One unfortunate sharp injury has the potential to ruin a young physician’s life. Sharps are to be handled carefully and disposed off in proper manner (Figs 1.4A and B). In case of accidental prick, postexposure prophylaxis is to be ensured in accordance with current standards.
 
Attention to Infection
Infections are usually uncommon but while implanting devices can be devastating. Strict surgical scrub for the first case is must and then self drying antiseptic handwash solutions are feasible. However, when implanting devices a surgical scrub before each case is mandatory. The six steps of handwashing must be adhered to religiously. Removal of hair from access site (avoid blades!!), use of antiseptic on skin and sterile drape form core of patient preparation. Sterile gown, cap, mask and gloves suffice for operator. Disposable sterile covers for the image intensifier and radiation shields should be placed when these are used over or next to the sterile field. Antibiotics prophylaxis is not needed unless large devices are left inside body.
 
Look Out for CIN
Contrast nephropathy is potentially disastrous complication which can be definitely be ameliorated by proper attention to basic principles of good practice. The incidence varies according to the definition used to quantify rise in serum creatinine—0.5 mg% absolute increase or 25% increase from baseline.
Estimation of GFR is mandatory in all cases and eGFR < 60 mL/min would mandate the use of established renoprotective strategy. Infusion of either normal saline or sodium bicarbonate at 1–1.5 mL/kg/min starting 3–12 hours before and continued up to 6–8 hours postprocedure is recommended. Limiting the total dye and use of iso-osmolar contrast or low osmolar contrast are additional safe guards. A contrast volume/creatinine clearance ratio of 3.7 has been suggested as a ceiling for contrast use to reduce nephrotoxicity risk. Otherwise, a ceiling of 30 mL and 100 mL of contrast media for diagnostic and therapeutic procedures can be used. Withholding all potential nephrotoxic drugs (NSAIDs, metformin) and repeating creatinine at 48 hours are also advisable. Biplane angiography when available also helps in limiting contrast volume. Deferring Adhoc PCI also helps kidneys to recover from initial insult in between two procedures. Typically, a gap of at least 10 days is sufficient. N-acetyl cysteine use is now no longer recommended in light of recent data showing questionable benefit (Fig. 1.5).
 
After the Table
In this phase, two essential requirement are access site management and appropriate orders for postoperative management.8
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Fig. 1.5: Suggested protocol for preventing contrast-induced nephropathy
 
Final Communication
After the procedure, the physician should communicate about the results of procedure in brief with patients and relatives. In case of any complications and unusual anatomical findings encountered, it should be informed along with the rectification measures taken. This is the time to emphasize the need for further procedures, if any, need for dual antiplatelet therapy and risks in periprocedural period.
 
Access Site Management
Proper management of access site is last crucial link of the procedure. Femoral sheath removal under local anesthesia obviates the pain and associated vasovagal reflex. When heparin has been used, one should wait for activated clotting time (ACT) to return to normal (<180) for giving manual compressions after sheath removal. For bivalirudin and LMWH use during PCI, ACT estimation is not warranted. Sheath removal and compression can be started after 2 hour following cessation of bivalirudin infusion. In case of LMWH use, one can commence removal 8–12 hours after last dose.
The sheath size usually determines the amount of bed rest needed after its removal. A minimum of 1–2 hours after the procedure for 4- to 5-F sheaths, whereas 2–4 hours for 6- to 8-F sheaths is common practice. With the use of vascular closure devices, the holding times may can be reduced to 1–4 hours. Assessment of adequacy of groin site hemostasis and peripheral pulses is necessary prior to ambulation. One should always auscultate the femoral access site prior to discharge. In case of a new audible bruit or a palpable mass a local site, a vascular ultrasound will be needed to exclude pseudoaneurysm or fistula.
Radial access offers easy ambulation and is being employed increasingly. Sheaths are removed immediately following procedure regardless of nature of anticoagulation. Compression is conveniently achieved by pneumatic wristband compression devices and arm immobilization for few hours is recommended.
 
Postprocedure Instructions
With more and more daycare diagnostic procedures, discharge directly from Cath Lab is common occurrence. Hence, cath lab staff should give proper general instructions and adjust medications before discharge. It is ideal to have vital signs monitored every 15 min for first few hours postprocedure by trained personnel or residents. For in-hospital patients, procedure team should give legible instruction for medication, access site and patient monitoring. At discharge an appropriate date for follow-up should be intimated.
 
CONCLUSION
Cardiac catheterization lab performs life-saving procedures in patients with heart disease. Open communication, informed consent and meticulous preprocedure evaluation are three pillars that lay the foundation to reduce procedural complications and improve patient satisfaction. Additional elements of good Cath Lab practices would be attention to radiation safety, infection control and predischarge guidance. There should be continued emphasis on teaching, training and building a good team (Fig. 1.6).9
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Fig. 1.6: Key elements for sustaining a successful Cath Lab team
SUGGESTED READING
  1. Bashore TM, Balter S, Barac A, Byrne JG, Cavendish JJ, Chambers CE, et al. 2012 American College of Cardiology Foundation/Society for Cardiovascular Angiography and Interventions Expert Consensus Document on Cardiac Catheterization Laboratory Standards Update. Journal Am Coll Cardiol. 2012; 59: 2221–305.
  1. Haynes AB, Weiser TG, Berry WR, Lipsitz SR, Breizat AH, Dellinger EP, et al. A surgical safety checklist to reduce morbidity and mortality in a global population. N Engl J Med. 2009; 360: 491–9.
  1. Hirshfeld JW Jr, Balter S, Brinker JA, et al. ACCF/AHA/HRS/SCAI clinical competence statement on physician knowledge to optimize patient safety and image quality in fluoroscopically guided invasive cardiovascular procedures: a report of the American College of Cardiology Foundation/American Heart Association/American College of Physicians Task Force on Clinical Competence and Training. J Am Coll Cardiol. 2004; 44: 2259–82.
  1. Kern MJ. The Cardiac Catheterization Handbook. Sunders, Elsevier.  Philadelphia, PA:  2011. pp. 1–37.
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  1. The Checklist Manifesto: How to Get Things Right. Non-fiction book by Atul Gawande. Henry Holt and Company. 
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